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• Soft tissue is defined as complex of
nonepithelial extra skeletal structure of body
exclusive of supportive tissue of various
organs and the hematopoietic/ lymphoid
• It is composed of fibrous tissue, adipose
tissue, skeletal muscle, blood and lymph
vessels and peripheral nerve.
• Most of the soft tissue derived from
mesoderm with neuroectodermal
contribution corresponding to peripheral
• 40%- lower extremity specially Thigh.
• 30%- trunk and retro peritoneum.
• 10%- upper extremity.
• 10% - head and neck.
• Males are affected more than females(1.4 : 1)
• Incidence – increases with age
EFFECT OF TUMOR DEPTH: SAME PATTERN
BUT DIFFERENT DIAGNOSIS
• Specific sarcoma tend to be occur in certain
age group –
• Children- Rhabdomyosarcoma ,
• Young adulthood- synovial sarcoma
• Middle to Late adult life- liposarcoma
French Federation Grading System Of Sarcoma
• Score 1: Sarcoma closely resembling normal adult
mesenchymal tissue Ex- Well differentiated liposarcoma
• Score 2: Sarcoma for which hitological typing is certain
Ex- Biphasic synovial sarcoma, Alveolar soft part sarcoma
• Score 3: Embryonal sarcoma, Undifferentiated sarcoma
and sarcoma of doubtfull tumor type
French Federation Grading System Of Sarcoma
• Score 1: 0 to 9 mitoses per 10 fields
• Score 2: 10 to 19 mitoses per 10 fields
• Score 3: More than 20 mitoses per 10 fields :
French Federation Grading System Of Sarcoma
• Score 0: No necrosis
• Score 1: < 50 % Tumor necrosis for all the
examined tumor surface
• Score 2: Tumor necrosis on more than half of the
examined tumor surface
French Federation Grading System Of Sarcoma
• Grade 1: 2 or 3
• Grade 2: 4 or 5
• Grade 3: Represent a total of 6, 7 or 8
Enneking Staging System For Soft Tissue Sarcoma
• Stage 1:
G1 Without metastases T1
G1 Without metastases T2
• Stage 2:
G2 Without metastases T1
G2 Without metastases T2
• Stage 3 :
G1 orG2 With metastases T1
G1 orG2 With metastases T2
• Reactive pseudoarcomatous proliferations are non
neoplastic lesions that either develop in response to
trauma or idiopathic.
• Clinically they are alarming because they develop suddenly
and grow rapidly.
• Example include
• Nodular fascitis
• Proliferative fascitis
• Proliferative myositis
• Myositis ossificans
• Pyogenic granuloma
• Most common pseudosarcoma
• Most often occur in adults and volar aspect of
• Gross – several centimeters in diameter , nodular
configuration, poorly defined margins.
• Microscopy –richly cellular ,plump immature
• A feature of diagnostic significance is the
presence of undulating wide bands of collagen
lined on the sides by spindle cells.
Calcifying aponeurotic fibroma
• Hand or wrist of a child or adolescent
• it may appear as a nodule or as an ill-defined
infiltrating mass in the subcutaneous tissue or
attached to a tendon
• Microscopic- the lesion is characterized by a
diffuse fibroblastic growth in which spotty
calcification occurs. Infiltration of fat and striated
muscle is often seen at the periphery. Mitoses are
scarce, and atypical cytologic features are absent.
Scattered osteoclast-like giant cells are frequently
• The skeletal muscles of the shoulder, thorax, and
thigh are those most commonly affected.
• Most patients are over the age of 45 years
• Gross- ill defined scar-like indurations of the
• Microscopic-a cellular proliferation rich in
fibroblasts is seen surrounding individual fibers.
The hallmark of the lesion is the presence of very
large basophilic cells with vesicular nuclei and
very prominent nucleoli.
• It is a reactive condition that is sometimes mistaken
microscopically for osteosarcoma.
• The term is inaccurate because the muscle may not be
involved, and inflammation is virtually absent.
• A history of trauma is obtained in only half of the
• The most common locations are the flexor muscles of
the upper arm (especially the brachialis anticus), the
quadriceps femoris, the adductor muscles of the thigh,
the gluteal muscles,
• Microscopic- there is a highly cellular stroma
associated with new bone and, less commonly,
• In an early lesion, the centrally placed areas may
be very difficult to distinguish from osteosarcoma
because of their extreme cellularity.
• The most important diagnostic feature is
provided by the maturation pattern (‘zonal
phenomenon’), characterized by a central cellular
area, an intermediate zone of osteoid formation,
and a peripheral shell of highly organized bone
Various appearances of myositis ossificans. A, Deep region showing a
highly cellular appearance that can simulate a soft tissue sarcoma. B,
Midportion showing osteoid formation by plump osteoblasts. C,
Peripheral portion showing a shell of well-formed bone
Almost exclusively the subscapular region of elderly
There is often a history of strenuous manual labor.
Microscopic-collagen bundles alternate with numerous
acidophilic, refractive cylinders often containing a central
dense core, both of which stain strongly with elastic stains.
Ultrastructurally- the cylinders are made up of immature
amorphous elastic tissue, whereas the central core contains
Elastase digestion fully removes this material.
Immunohistochemically- the cells present in the lesion are
positive for CD34, MEF-2, prominin 2 (CD133), and factor
1 Proliferation of well-differentiated fibroblasts
2 Infiltrative pattern of growth
3 Presence of a variable (but usually abundant)
amount of collagen between the proliferating
4 Lack of cytologic features of malignancy
5 Scanty or absent mitotic activity
6 Aggressive clinical behavior characterized by
repeated local recurrences but lack of capacity to
• Grossly, these lesions are often large, firm,
and whitish, with ill-defined outlines and an
irregularly whorled cut surface. They often
arise in a muscular fascia.
• Microscopically, most of the proliferating cells
have features intermediate between those of
fibroblasts and smooth muscle cells
The spindle cells of fibromatosis grow diffusely
between skeletal muscle fibers
Common tumors of adults, although they can
occur in any age group and even be present as
Fibrosarcomas can arise from superficial and deep
connective tissues such as fascia, tendon,
periosteum, and scar; grow slowly or rapidly; and
often appear well circumscribed.
They usually are soft and cellular and may contain
areas of necrosis and hemorrhage
• Microscopic- The cells are arranged in fascicles
that intersect each other at acute angles,
resulting in a herringbone appearance.
• The individual cells resemble normal
fibroblasts, and a reticulin stain demonstrates
abundant fibers wrapped around each cell.
• It should be differented from monophasic
synovial sarcoma, liposarcoma, malignant
fibrous histiocytoma, and MPNST.
• Immunohistochemically the prototypical
fibrosarcoma should have reactivity for
vimentin and type I collagen but not for
smooth muscle markers, histiocytic markers,
or basal lamina components
Congenital fibrosarcoma (infantile
• is an extremely cellular tumor characterized
by very rapid growth and the capability for
extensive local invasion, but its metastatic rate
• At the molecular level, it is characterized by
the ETV6–NTRK3 gene fusion, which results
from the chromosomal translocation
Congenital fibrosarcoma. The tumor is extremely
cellular and mitotically active
Sclerosing epithelioid fibrosarcoma
• It is a variant of fibrosarcoma ,It is composed of small,
round to ovoid tumor cells embedded in a dense
• The scanty cytoplasm often has a clear appearance,
and there may be an Indian file pattern of growth .
Necrosis and bone invasion may be found.
• There is consistent positivity for vimentin, and
occasional positivity for EMA and even for keratin.
• The tumor is associated with a high incidence of local
recurrence and distant metastases
Inflammatory Myofibroblastic Tumor
• Which blends imperceptibly with cases that
have been reported as inflammatory
pseudotumor on one hand and inflammatory
fibrosarcoma on the other.
• Many of the cases have occurred in the
mesentery or retroperitoneum of children or
Benign Fibrous Histiocytoma
• Tenosynovial giant cell tumor
• Pigmented villonodular synovitis
The microscopic- A variable mixture of histiocyte-
like cells (some foamy, others multinucleated, still
others containing hemosiderin) and fibroblast-
like cells is always present. Some lesions can be
extremely cellular (cellular variant), and some
may have large atypical nuclei (atypical variant),
Tenosynovial giant cell tumor. A polymorphic infiltrate of small histiocytes
and multinucleated giant cells is embedded in dense fibrous tissue
Intermediate (borderline) fibrous
• This vaguely defined group of tumors is characterized by local
aggressiveness but an extremely low rate of distant metastases.
• Dermatofibrosarcoma protuberans (DFSP)-
• It is typically centered in the dermis, but it can also occur in deeper
• Microscopically - lack of circumscription; high cellularity; a
relatively monomorphic appearance; nuclear hyperchromasia;
moderate to high mitotic activity; lack or inconspicuousness of
giant, foamy, or hemosiderin-laden cells; and the presence of what
has been called a storiform pattern of growth .
• This refers to a peculiar arrangement of the tumor cells around a
central point, producing radiating ‘spokes’ grouped at right angles
to each other.
• dermatofibrosarcoma protuberans have a
translocation that involves chromosomes 17
• looks like the usual dermatofibrosarcoma
protuberans except for the presence of a
population of dendritic cells heavily loaded
Malignant Fibrous Histiocytoma
• Several morphologic variants of MFH have been
• Storiform-pleomorphic MFH is the prototypic and
most common member of this group.
• Most cases occur in the deep soft tissues of
extremities in adults, with a peak in the seventh
decade, but cases have also been recorded in children.
• Some develop at the site of previous radiation therapy.
• Still others have appeared around an infarct or a
foreign body or at the site of a surgical scar.
Malignant Fibrous Histiocytoma
• Microscopic features - the presence of highly
pleomorphic tumor cells and a storiform pattern of
• Sometimes the cytoplasm of the giant tumor cells is
seen to contain numerous variably sized hyaline
globules, thought to be related to apoptosis and
lugubriously called thanatosomes.
• Inflammatory elements, such as lymphocytes, plasma
cells, and eosinophils, are usually mixed with the
• Metaplastic bone and cartilage formation may be
• Immunohistochemically, there is usually
reactivity for vimentin, a1-antitrypsin, a1-
antichymotrypsin, KP-1 (CD68), factor XIIIa,
ferritin, and the plasma proenzyme factor XIII.
• is the term currently preferred for the tumor also known as
• Most of these tumors arise in the extremities of adults.
• Grossly, they are mucoid and resemble myxoid
• Microscopically, the low-grade forms exhibit an abundant
matrix of acid mucopolysaccharides, high vascularity, and
the presence of cells resembling lipoblasts.
• They are distinguished from myxoid liposarcomas by the
presence elsewhere in the tumor of typical areas with the
storiform–pleomorphic MFH pattern and the absence of
Low-grade fibromyxoid sarcoma
• Usually deep but sometimes superficial,
especially in children
• Characterized by alternating fibrous and myxoid
areas, a focally whorled pattern of growth, low
cellularity, and a bland appearance of the
fibroblastic spindle cells[
• The main differential diagnosis is with
myxofibrosarcoma. Low-grade fibromyxoid
sarcoma has a biphasic fibrous and myxoid
appearance, and the vascular network is less well
hyalinizing spindle cell tumor with
• Morphologic variant of low-grade fibromyxoid
sarcoma characterized by the presence of
huge rosettelike formations made up of
Hyalinizing spindle cell tumor with
Inflammatory myxohyaline tumor
• low-grade malignant tumor usually found in the distal extremities .
• Microscopically, it has an infiltrative multinodular quality and a
polymorphic cellular composition in a hyaline or myxoid
• There is a dense mononuclear inflammatory infiltrate containing
scattered stromal cells of either epithelioid or spindle shape. Some
of the latter are very large, with bizarre nuclei and prominent
nucleoli, resulting in a resemblance to Reed–Sternberg cells or
• The immunohistochemical profile, which is nonspecific, includes
occasional focal reactivity for keratin. Local recurrence is common,
but distant metastases are exceptional.Recently, this neoplasm is
shown to exhibit a recurrent genetic aberration t(1;10)(p22;q24),
• The neoplastic cells are mixed with, and even
obscured by, an intense inflammatory
infiltrate rich in neutrophils.
• Some of the tumor cells contain phagocytosed
neutrophils in their cytoplasm. Storiform
pattern, collections of foamy cells, and areas
of tissue necrosis are also consistently present
Plexiform fibrohistiocytic tumor
• occurs chiefly in children and young adults.
• It usually presents as a small, slow-growing dermal or
subcutaneous mass, often in an upper extremity.
• Microscopically, there is a multinodular or plexiform
proliferation of fibroblast-like and histiocyte-like cells
admixed with osteoclast-like giant cells.
• They have been divided morphologically into three
• histiocytic (often with osteoclast-type giant cells),
• and mixed.
• extremities of children and young adults as a
circumscribed, multinodular, or multicystic
• Microscopically, highly cellular foci are mixed with
focal areas of hemorrhagic cyst-like spaces and
large aggregates of chronic inflammatory cells.
The latter are often arranged at the periphery of
the tumor in the form of lymphoid follicles and
may simulate the appearance of a lymph node.
• Proliferative lesions of peripheral nerves are
• Non-neoplastic - traumatic neuroma.
• Benign tumors - schwannomas,
neurofibromas, and perineuriomas.
• Malignant tumors-malignant peripheral nerve
sheath tumors (MPNSTs)
The large majority of neuromas follow trauma – hence their
designation as traumatic neuromas.
Amputation neuroma, a term made popular during the First World
War, is a type of traumatic neuroma in which the original trauma
involves the loss of part or all of an extremity
This lesion may be exquisitely painful
Microscopically, all the elements of a nerve can be recognized: axons,
Schwann cells, perineurial cells, and fibroblasts In addition, scar
tissue is often present.
Immunohistochemically, the Schwann cells of traumatic neuroma
show CD68 and Ki-M1-P.
• Truly encapsulated neoplasms
• Almost always solitary
• Its most common locations are the flexor surfaces of the
extremities, neck, mediastinum, retroperitoneum, posterior spinal
roots, and cerebellopontine angle.
• The nerve of origin often can be demonstrated in the periphery,
flattened along the capsule but not penetrating the substance of
the tumor .
• Since this is a benign neoplasm that only rarely recurs .
• The great majority of cases occur sporadically.
• A small percentage of cases are associated with neurofibromatosis
type 2 (caused by a germline mutation in the NF2 gene located on
22q12, which encodes merlin, also known as schwannomin
• immunoreactivity for S-100 protein, calretinin (in contrast
to neurofibromas), calcineurin, basal lamina components
,vimentin, nerve growth factor receptor, lipocortin-1, and
sometimes glial fibrillary acidic protein and KP-l
• Palisading of nuclei is not unique to schwannoma.
• It can also occur in leiomyoma, leiomyosarcoma,
• calcifying aponeurotic fibroma,
• non-neoplastic smooth muscle
• (most commonly in the appendiceal wall).
• It is the term used for highly cellular
schwannomas that are exclusively composed
of Antoni A areas but lack Verocay bodies.
• These changes can be accompanied by nuclear
atypia, mitotic activity, and focal necrosis.
• Most reported cases have been in the
retroperitoneum, pelvis, and mediastinum
• Most arise from the spinal nerve roots.
• Microscopically by the presence of melanin
pigmentation and the deposition of psammoma
• In contrast to all other types of schwannoma
described in this section, the psammomatous
melanotic variety is regarded as a low-grade
malignancy because of its tendency for local
recurrence and the fact that a few of the
reported cases have metastasized
• The gross appearance of -As a rule, the tumors are not
encapsulated and have a softer consistency than
• The more superficial tumors appear as small, soft,
pedunculated nodules protruding from the skin
• Deeper tumors grow larger. Tumors resulting in diffuse
tortuous enlargement of peripheral nerves are designated
as plexiform neurofibromas and are usually seen in the
context of type 1 neurofibromatosis (caused by a germline
mutation in the NF1 gene located on 17q11.2, which
Well-circumscribed neurofibroma of soft tissue.
The tumor has a gelatinous appearance
Typical gross appearance of plexiform neurofibroma.
This tumor variety is indicative of Recklinghausen
• Microscopic- Neurofibromas are formed by a combined
proliferation of all the elements of a peripheral nerve:
axons, Schwann cells, fibroblasts, perineurial cells .
• Axons can be demonstrated by silver or
acetylcholinesterase stains or by immunostaining for
neuron-specific enolase (NSE), neurofilaments, or various
• Schwann cells usually represent the predominant cellular
element. Most have markedly elongated nuclei, with a
wavy, serpentine configuration and pointed ends.
• In contrast to schwannomas, Verocay bodies, palisading of
nuclei, and hyaline thickening of the vessel wall are
almost always absent in neurofibromas
- single-gene disorder, autosomal-dominant
. Two forms.-
- von Recklinghausen disease (neurofibromatosis type 1),
patients have multiple café-au-lait spots and dermal
- Neurofibromatosis type 2, patients have predominantly
bilateral acoustic neuromas (schwannomas) that are
associated with other brain and spinal cord tumors.
• It is diagnosed based on the presence of any two of the
1. At least five café-au-lait spots larger than 5 mm (six larger
than 15 mm if the patient is prepubertal)
2. Two or more neurofibromas of any type or one plexiform
3. Multiple large freckles in the axillary or inguinal regions
4. Sphenoid wing dysplasia
5. Bilateral optic nerve gliomas
6. Multiple iris nodules (Lisch spots)
7. A first-degree relative with the preceding criteria
• Benign tumors of the peripheral nerve composed predominantly or
exclusively of perineurial cells are being increasingly
recognized.Microscopically, they are composed of extremely elongated
cells arranged in parallel bundles.
• Some cases have a storiform pattern of growth and may correspond to
the former storiform perineurial fibromas.
• There is an intraneural variant of perineurioma,
• Other recently recognized variants of this tumor include sclerosing
perineurioma, which has a predilection for the fingers and palms of young
adults;[reticular (retiform) perineurioma, with a predominant lace-like or
reticular growth pattern composed of anastomosing cords of spindle cells;
• plexiform perineurioma;and the exceptionally rare granular cell
• Hybrid forms of schwannoma and perineurioma have also been described,
• as well as malignant forms of perineurioma, the latter representing a
subtype of MPNST
Malignant peripheral nerve sheath
• It is the currently preferred term for the
neoplasm also known over the years as
malignant schwannoma, neurogenic sarcoma,
• Approximately half of these tumors arise de
• The other half from nerves involved by
neurofibromas as part of type 1 Recklinghausen
• Some have occurred in areas of previous
Malignant peripheral nerve sheath
• Because of its difficult microscopic recognition,
errors are often made.
• There are two circumstances in which the
diagnosis of MPNST should be the primary
consideration in the presence of a malignant
tumor of soft tissues composed of spindle cells:
(1) when the tumor develops in a patient with
type 1 Recklinghausen disease;
• (2) when the tumor is obviously arising within
the anatomic compartment of a major nerve or in
continuity with a neurofibroma.
Malignant peripheral nerve sheath
• In the absence of these circumstances the light microscopic
diagnosis of MPNST is
• They include: serpentine shape of the tumor cells;
• Arrangement in palisades or whorls;
• Marked contrast between the deeply hyperchromatic nuclei and
the pale cytoplasm (‘punched-out nuclei’);
• Perivascular concentration of tumor cells, with a plumper shape;
• Epithelioid appearance of the endothelial cells of these vessels;
• Presence of large gaping vascular spaces, resulting in a
• Geographic areas of necrosis, with tumor palisading at the edges
The contrast between the dark hyperchromatic nuclei and the
light cytoplasm is typical of malignant peripheral nerve sheath
• Benign fatty tumors can arise in any location in which fat is normally
• The majority occur in the upper half of the body, particularly the
trunk and neck, but they can develop in any other site, including
hands and feet.[
• Most lipomas are subcutaneous, an important point in the
differential diagnosis with liposarcomas, which are almost always
• However, lipomas can also occur in the deep soft tissues; these are
subclassified into intramuscular (most common in the trunk) and
intermuscular (most common in the anterior abdominal wall).
• Most patients are in the fifth or sixth decade of life
• May be single or multiple.
• Lipomas can grow to a large size;
• they are usually encapsulated when located in the
superficial soft tissues
• Poorly circumscribed when arising in deeper
• Grossly, lipomas consist of bright yellow fat separated
by fine fibrous trabeculae .
• Microscopic- they are composed of mature adipose
tissue with no cellular atypia.
• They are cytologically and immunohistochemically
indistinguishable from normal fat, including positivity
for S-100 protein and calretinin.
Morphologic variations of lipomas :
• 1 Fibrolipoma - characterized by the presence of
prominent bundles of mature collagenous or
myxocollagenous stroma intermixed with mature
adipocytes. It affects mainly the distal extremities.
2 Myxolipoma. This tumor features focally well-
developed myxoid changes.
3 Chondroid lipoma. This variant is usually deep-seated
. It is characterized by a component of eosinophilic and
vacuolated cells containing glycogen and lipid that
resembles brown fat cells, lipoblasts, and chondroblasts .
• 4- Myolipoma. This tumor is characterized by an admixture in variable
proportions of mature adipose tissue and bundles of well-differentiated smooth
5 Spindle cell lipoma.- Characteristically located in the regions of the shoulder
and posterior neck of adults, but also found in many other locations,
It is composed of an admixture of mature lipocytes and uniform spindle cells set
in a mucinous and fibrous background[
Features that assist in distinguishing it from myxoid liposarcoma
include the absence of lipoblasts
and of a prominent plexiform vascular pattern,
the presence of thick (‘ropy’) collagen bundles,
and the great uniformity of the proliferating small spindle cells.
• 6 Pleomorphic lipoma. This is a lipoma containing
hyperchromatic multinucleated (‘floret-like’) tumor
cells within the fibrous septa traversing the neoplasm .
• As for spindle cell lipoma, its most common location is
the shoulder and posterior neck region.
• Differential diagnosis is with the sclerosing form of)
well-differentiated liposarcoma (atypical lipomatous
• The location of the lesion is an important clue,
• Proportion of floret-type giant cells and lipoblasts is
the most important distinguishing feature at the
• 7 Angiolipoma. They are often painful and
• They are located in the subcutis, most commonly on the
trunk or extremities.
• Vascularity often is limited to a band of tissue on the
periphery of the neoplasm .
• Hyaline thrombi are common and constitute an important
• The pain correlates well with the degree of vascularity.[
Intimate admixture of blood vessels
and mature adipose tissue Hyaline thrombi in angiolipoma
• Affects almost exclusively infants and young children
(below the age of 5 years).
• It commonly involves the proximal portion of the lower
and upper extremities.
• Grossly, the lesion is soft and lobulated .
• It is subdivided into (benign) lipoblastoma (sometimes
also designated as embryonal or fetal lipoma) when
well circumscribed and
• lipoblastomatosis when deep-seated and ill defined.
• Microscopic- it closely resembles fetal fat. presence of
lipoblasts, a plexiform vascular pattern, and an
abundant myxoid stroma .
• It may be confused with myxoid liposarcoma.
• It is distinguished from the latter by
• virtue of the young age of the patient,
• distinct lobulation,
• and absence of giant cells or pleomorphic
• is a rare benign neoplasm.
• Location- interscapular region, axilla, and thigh,
but also in the mediastinum and
• Gross-Its cut surface has a typical brown color,
Microscopic- pattern is characteristic – an
organoid arrangement of large cells with centrally
located nucleus and a cytoplasm filled with many
small vacuoles that stain for neutral fat.
Gross exhibiting the typical light
brown cut surface
• It is the most frequent soft tissue sarcoma in
• Liposarcomas are usually large and occur most
frequently in the lower extremities (popliteal
fossa and medial thigh); retroperitoneal,
perirenal, and mesenteric region; and shoulder
• Grossly, liposarcomas are well circumscribed but
• The common morphologic denominator of
liposarcoma is the lipoblast .
• This appears as a mononuclear or multinucleated
cell with one or more cytoplasmic vacuoles that
• The nucleus may be pushed aside by a single
large vacuole, resulting in a signet ring
• or it may remain centrally located but exhibit
small indentations by multiple small vacuoles.
• Enzinger and Winslow divided liposarcomas
into four types:
• Round cell,
• Well differentiated,
• Most common type of liposarcoma.
• Marked predilection for the lower extremities, particularly the
• It practically never occurs in the retroperitoneum.
• Microscopically, myxoid liposarcoma has few or no mitotic figures
• and is characterized by proliferating lipoblasts
• Prominent anastomosing capillary network,
• and a mucoid matrix.
• The presence of a delicate network of thin-walled vessels is an
important feature in the differential diagnosis with myxoma and
other myxoid tumors.
• Cytogenetically, myxoid liposarcoma is
characterized by the reciprocal translocation
Round cell type
• The tumor cells are small and have a distinctly
acidophilic cytoplasm .
• The presence among them of scattered
lipoblasts establishes the diagnosis.
• Mitoses are more and vascular network is
less marked than myxoid form.
Atypical lipomatous tumor orwell-
• Gross- resembles ordinary lipoma .
• It also resembles it on low-power examination,
• but closer inspection shows scattered tumor cells with
large, deep-staining nuclei.
• These atypical cells may concentrate on the fibrous
strands that traverse the adipose tissue lobules
• or be scattered among the mature adipocytes (lipoma-
like subtype) .
Atypical lipomatous tumor
Sclerosing pattern Lipoma-like subtype of
• It is a highly cellular,
• poorly differentiated neoplasm containing
numerous tumor giant cells,
• some of them having the features of
• foci of necrosis.
Epithelioid variant of pleomorphic liposarcoma
• It is the term used for the emergence of a generally
nonlipogenic component within an atypical lipomatous
• The dedifferentiated component may already be
present at the time of the original excision OR in
recurrent or metastatic foci.
• It is much more common in retroperitoneal neoplasms.
• Microscopic- the dedifferentiated component is
usually high grade.
• Heterologous elements, such as skeletal muscle
(particularly frequent cartilage or blood vessels, may
TUMORS AND TUMOR LIKE
CONDITIONS OF BLOOD AND
• occupy a gray zone between hamartomatous malformations and true
• They are frequently designated and regarded as tumors because of their
usually localized nature and mass effect.
• However, the fact that they consistently lack chromosomal alterations
speaks against a true neoplastic nature.
• The presence or absence of nerve bundles intimately admixed with the
vascular proliferation has been used to place them into a malformative or
a neoplastic category.
• A high percentage occurs in children, and many are already present at
• Over half of the cases are in the head and neck area; they can also occur in
the trunk or extremities.
• Most hemangiomas are solitary
• Made up of small vessels of capillary caliber and can occur in any
• Its most common location is the skin,
• where it appears as an elevated nodule with an intense crimson
color. Such a hemangioma is traditionally known to dermatologists
as a strawberry hemangioma because of its clinical appearance.
• Microscopic- the lesion exhibits a vaguely lobular configuration on
low-power examination . Masses of closely packed spindle cells are
seen with neoformed spaces that contain little blood.
• Mitotic figures are usually present and can be numerous. At the
periphery, the tumor may be seen to invade subcutaneous tissue or
skeletal muscle. Perineurial involvement has also been observed.
• Mast cells may be numerous.
The high cellularity and mitotic activity
should not lead to an overdiagnosis of
• Those occurring in the skin are traditionally
known as port-wine nevus or nevus flammeus.
• This lesion, which is present at birth, grows very
slowly and in proportion to the growth of the
patient; in time, it becomes nodular and soft.
• In contrast to the strawberry nevus, it does not
• Are composed of larger vessels with cystically
dilated lumina and thin walls
The vascular spaces are widely dilated
• Also known as glomangioma,
• originates in the neuromyoarterial glomus, a
normal arteriovenous shunt abundantly
supplied with nerve fibers and fulfilling a
• The classic location of the glomus tumor is
the subungual region, but it can occur
elsewhere in the skin, soft tissues, nasal cavity,
• Microscopic- glomus tumors consist of blood
vessels lined by normal endothelial cells and
surrounded by a solid proliferation of round or
cuboidal ‘epithelioid’ cells with perfectly
round nuclei and acidophilic cytoplasm .
• Immunohistochemically, they manifest
reactivity for myosin, vimentin, actin, and
basal lamina components but usually not for
Glomus tumor- The distribution of round
glomus cells around the open vascular
lumen is a key to the diagnosis
• This tumor is usually found in the soft tissues of
the extremities (usually distal).
• Tends to have a multinodular pattern of growth
• There is a family of tumor types composed of
cells with pericytic features, which blend on one
side with vascular smooth muscle cells and on
the other with vascular glomus cells.
• Presence of branching vessels with a staghorn
Characteristic multinodular quality as
seen on low power.
High-power view showing a cytologic
appearance intermediate between that
of glomus cells and pericytes
• Vascular tumors of an endothelial nature that
occupy an intermediate position between the
benign hemangioma and the full-blown
• Is composed of a distinctive type of endothelial cells
having an epithelial-like or histiocyte-like
appearance. The cytoplasm is abundant and
eosinophilic, often vacuolated. The nucleus is
round, vesicular, and occasionally indented.
Vascular lumina are present, most of them small;
some are located intracellularly and are responsible
for the cytoplasmic vacuolation
A, The tumor partially fills the
lumen of the femoral vein.
B, Prominent cytoplasmic vacuolization is
apparent on high-power examination of the
Malignant endovascular papillary
angioendothelioma (Dabska tumor; papillary
• Is an extremely rare tumor.
• Usually seen in children
• Located in the skin or soft tissues and
• Characterized by papillary tufts that are lined by
plump endothelial cells located within dilated
vascular lumina, some of which have a
• Many of the tumor cells have epithelioid or
histiocytoid features, including cytoplasmic
eosinophilia and vacuolation.
The papillary configuration of the endothelial
fronds can be appreciated
• It is usually seen in adults and the elderly.
• The most common locations are the skin, soft
tissue, breast, bone, liver, and spleen.
• Some soft tissue angiosarcomas arise from
major vessels, such as the inferior vena cava,
pulmonary artery, or aorta.
• Angiosarcomas have been reported in previously
• Around long-standing foreign bodies,
• In arteriovenous fistulas(including surgically
• As a secondary somatic-type development in
mediastinal or retroperitoneal germ cell tumors,
• Arising within preexisting benign tumors, such as
neurofibroma, intramuscular lipoma, or
• Grossly, angiosarcomas tend to be highly hemorrhagic and
• Their microscopic appearance ranges from a pattern so
well differentiated as to simulate a benign hemangioma to
one so undifferentiated and solid as to simulate carcinoma,
malignant melanoma, or other types of sarcoma.
• The diagnostic areas of angiosarcoma are represented by
the freely anastomosing vascular channels lined by atypical
• A pattern that is accentuated by silver reticulin stains or
immunostains for basement membrane components.
Clusters of reactive lymphocytes and clumps of
hemosiderin are common.
• Variations in the appearance of the neoplastic
endothelial cells are great.
• Their shape ranges from very elongated to
plump and epithelioid, and their size from
small to giant, with occasional development of
• The latter are sometimes seen to display
prominent hyaline globules containing a1-
antitrypsin and a1-antichymotrypsin.
Gross hemorrhagic appearance of angiosarcoma in the
region of the hip
On high power, the channels are seen to
be lined by highly atypical endothelial cells
• Immunohistochemically -CD31 and FLI-1 are
the most reliable.
• Epithelioid variant there is coexpression of
• In other cases there is expression of D2-40,
suggesting differentiation toward lymph vessel
• Most lymphangiomas represent malformations rather than
true neoplasms and are thought to result from failure of
the lymphatic system to communicate with the venous
• Three forms exist: capillary, cavernous, and cystic .
• The capillary form occurs in the skin,
• Whereas the cavernous variety prefers deep soft tissues.
• Cystic lymphangioma has been traditionally known as
• Its most common presentation is in the form of a poorly
defined soft tissue mass in the neck of children, usually
situated posterior to the sternocleidomastoid muscle and
sometimes extending into the mediastinum
• Microscopically, lymphangioma consists of
large lymphatic channels growing in loose
connective tissue. A few disorganized bundles
of smooth muscle can be present in the wall
of the larger channels
Large cystic hygroma in the neck
of an 18-month-old infant.
Lymphangioma of soft tissue showing
dilated spaces lined by flattened
endothelium. A scattering of
lymphocytes is present in the stroma
• It is regarded as the lymph vessel counterpart of angiosarcoma.
• The cutaneous lymphangiosarcoma, present clinically as bluish or
• They are often multiple,
• Microscopically, they show a wide variation of patterns, ranging
from solid undifferentiated areas that can simulate carcinoma to
others so well differentiated as to be indistinguishable from
lymphangioma or lymphangiectasia .
• As in the case of (hem)angiosarcoma, the most typical areas are
represented by freely anastomosing channels lined by atypical
• immunohistochemical studies have not only documented the
presence of endothelial markers such as D2-40.
The diagnosis of lymphangiosarcoma has been
made in the presence of malignant vascular
tumors superimposed on areas of chronic
lymphedema, the prototypical example being
the lymphangiosarcoma developing in
patients who have had long-standing massive
lymphedema after radical mastectomy for
Amputated upper extremity in a case of
lymphangiosarcoma showing an
intricate network of neoplastic vessels
• Several types of leiomyoma exist.
• Cutaneous leiomyomas located in the dermis arise from arrectores
pilorum muscles; they are characteristically superficial, small,
multiple, and grouped.
• Genital leiomyomas are solitary tumors that arise from smooth
muscle bundles located in the superficial subcutaneous tissue of
genital areas and structures that are topographically and
functionally related to them, such as the nipple, areola, axilla,
scrotum, penis, vulvar labia, and anal skin.
• Vascular leiomyomas (angioleiomyomas) arise from the smooth
muscle of blood vessels. They occur more frequently in females and
are usually located in the soft tissues of the lower limbs.
• Grossly, vascular leiomyomas are yellow or
yellowish pink, sharply circumscribed, and
fairly firm .
• Microscopically, they are made up of
intersecting fascicles of smooth muscle cells
encircling vascular lumina lined by normal
endothelial cells .
Gross appearance of a soft tissue
leiomyoma located in the leg of a child
Vascular leiomyoma. The neoplastic smooth
muscle cells are clearly related to vessel walls
• Leiomyosarcoma of soft tissue is relatively rare.
• It is typically a tumor of adults and the elderly.
• The leiomyosarcomas seen with increasing frequency in
immunosuppressed patients (HIV-infected individuals and
organ transplant recipients) have been found to be
associated with the Epstein–Barr virus[
• Most soft tissue leiomyosarcomas are located in the
extremities, but they can occur anywhere, including the
head and neck region.
• Many arise from the walls of arteries and veins -inferior
vena cava, saphenous vein, femoral vein, pulmonary artery,
femoral artery, and aorta.
• Grossly, leiomyosarcomas can be as well
circumscribed as the leiomyomas but are
larger and softer and have a tendency for
fresh tumor necrosis, hemorrhage, and cystic
• Those arising from major vessels can protrude
in a polypoid fashion within the lumen or be
Gross appearance of leiomyosarcoma.
The central cystic cavity is a common
Leiomyosarcoma filling the lumen of the
popliteal vein and its branches, as seen on
• Microscopically, the pattern of growth is predominantly fascicular, with
the tumor bundles intersecting each other at wide angles. Merging of
tumor cells with blood vessel walls is an important diagnostic clue .
• In some cases the vascular pattern is particularly prominent, resulting in a
• We regard these tumors as the malignant counterpart of vascular
leiomyoma and have designated them vascular leiomyosarcomas.
• The individual cells have elongated, blunt-ended nuclei and acidophilic
• Palisading of nuclei may occur.
• Cytoplasmic vacuoles located at both ends of the nucleus, sometimes
indenting them, represent another diagnostic clue.
The intimate relationship of the tumor cells with the
• Bona fide soft tissue benign tumors of skeletal muscle origin are
• They can be divided into distinct subtypes, although some overlap
• Those known as the adult type are found almost exclusively in the
oral cavity and its vicinity in adult.
• Microscopically, the cells are well differentiated, large, rounded or
polygonal, with abundant acidophilic cytoplasm containing variable
amounts of lipid and glycogen.
• Some cells have features of ‘spider cells’, Cross striations and
intracytoplasmic rod-like (‘jack straw’) inclusions are frequent, and
intranuclear inclusions may be seen.
• There is no mitotic activity or nuclear atypia. The differential
diagnosis includes granular cell tumor, hibernoma, and the peculiar
condition known as crystal-storing histiocytosis
• The fetal form of rhabdomyoma is seen almost
exclusively in two locations: the head and neck area
(particularly the retroauricular area) in children under
3 years of age.
• The vulvovaginal region of middle-aged women.[he
latter, also referred to as genital rhabdomyoma.
• Microscopically, They are very cellular, formed by
immature skeletal muscle fibers (some containing cross
striations) and primitive mesenchymal cells . Nuclear
aberrations are absent, and mitoses are generally rare.
• The vulvovaginal cases tend to have a myxoid quality.
• There are three major categories of rhabdomyosarcoma: pleomorphic, embryonal,
• Pleomorphic rhabdomyosarcoma.-This tumor, which constituted practically all the
cases of rhabdomyosarcoma in the older literature, is actually the least common of
the three categories.
• It arises in areas where myotome-derived skeletal muscle occurs and is therefore
usually located in an extremity, especially the thigh.It occurs almost exclusively in
• Grossly, it may be confined within fascial compartments and have the shape of the
muscle from which it arises.
• Microscopically, the tumor is very pleomorphic, with numerous tumor giant cells.
• Making a differential diagnosis with pleomorphic liposarcoma and other types of
pleomorphic sarcoma is so difficult that a diagnosis of pleomorphic
rhabdomyosarcoma should not be made unless there is incontrovertible evidence
of skeletal muscle differentiation in the form of cross striations.
• One should be very careful to avoid the following
• (1) entrapped non-neoplastic skeletal muscle
• (2) release of myoglobin from necrotic muscle
with subsequent nonspecific absorption by tumor
cells, which thus become immunoreactive.
• (3) presence of skeletal muscle differentiation in
other malignant tumors.
Pleomorphic rhabdomyosarcoma. The tumor was
immunoreactive for desmin and skeletal muscle actin
• This tumor type is common in the head and
neck region), retroperitoneum, bile ducts, and
• The large majority occur in children between
the ages of 3 and 12 years.
• Grossly, the tumor is poorly circumscribed,
white, and soft.
• Microscopically, the tumor cells are small and
spindle shaped. Some have a deeply
acidophilic cytoplasm . A feature of diagnostic
value is the presence of highly cellular areas
usually surrounding blood vessels, alternating
with paucicellular regions that have abundant
myxoid intercellular material.
• Cross striations may or may not be present;
Embryonal rhabdomyosarcoma. Most of the nuclei are
oval; the cytoplasm is scanty and acidophilic
Embryonal rhabdomyosarcoma composed
predominantly of round cells. There is a
perivascular pseudorosette around a blood vessel
• When growing beneath a mucosal membrane,
such as the vagina, urinary bladder, or nasal
cavity, it frequently forms large polypoid masses
resembling a bunch of grapes – hence the name
• A highly characteristic feature of these polypoid
(‘botryoid’) tumors is the presence of a dense
zone of undifferentiated tumor cells immediately
beneath the epithelium, a formation known as
Nicholson cambium layer
Botryoid rhabdomyosarcoma of common bile duct
showing a concentration of tumor cells immediately
beneath the epithelium (‘cambium layer’).
• it predominates in an older age group -10–25
• and occurs more frequently in the extremities,
the most common locations being forearms,
arms, and perirectal and perineal regions.
• It also occurs in the head and neck region.
• Microscopically, small, round, or oval tumor cells are seen
separated in nests by connective tissue septa .
• The tumor cells in contact with these fibrous strands remain firmly
attached to them, but the others tend to detach because of a lack
of cohesiveness, which results in a typical alveolar or
• The deep acidophilia of the cytoplasm and the presence of
occasional multinucleated giant cells are important diagnostic
• Cases in which the alveolar pattern is poorly developed are
referred to as the ‘solid’ variant of alveolar rhabdomyosarcoma and
are particularly difficult to diagnose. Before identification of this
• Many of these tumors were misdiagnosed as primary malignant
lymphoma (of the soft tissues..
Gross appearance of alveolar
rhabdomyosarcoma. The tumor is
embedded within skeletal muscle
Typical low-power appearance of
alveolar rhabdomyosarcoma. Note
the small size of the tumor cells.
• Typically arises about the knee and ankle joints of children and
• It also occurs around other joints, such as shoulder and hip.
• Grossly, it tends to be well-circumscribed, firm, and grayish pink.
• Microscopically, the classic form of synovial sarcoma is that of a
biphasic tumor composed of sharply segregated epithelial and
sarcomatous components (the terms being used descriptively and
• The epithelial areas usually appear in the form of gland-like spaces
lined by cuboidal (synovial-like) or columnar cells, but can also
present as solid nests of large pale cells. It is exceptional for this
component to exhibit squamous features
• The sarcomatous component is made up of
spindle cells with a fibroblast-like appearance.
It tends to be hypercellular but with a
relatively monotonous appearance, plump
nuclei, a focally whorled pattern, distinct
lobulation or fasciculation.
Typical biphasic appearance of synovial sarcoma
Synovial sarcoma -with an adenocarcinoma-like
appearance of the epithelial component
Monophasic synovial sarcoma
• It is composed of only one of the two
• In the large majority of cases, this applies to the
spindle cell sarcomatous component, which is
easily misdiagnosed as fibrosarcoma,
• A search for epithelial-looking foci should be
carried out in these situations, as well as a
thorough immunohistochemical and
• possibly molecular evaluation
Granular cell tumor
• The classic location of tumor, is the tongue,
known as granular cell myoblastoma,.
• Other locations- skin, vulva, breast, larynx,
bronchus, esophagus, stomach, appendix,
rectum, anus, salivary glands, bile ducts,
pancreas, urinary bladder, uterus, brain,
Granular cell tumor
• These tumors are usually small, although we have
seen cases measuring up to 5 cm in diameter.
• They have a hard consistency and ill-defined
• The individual cells are large and their cytoplasm
is highly granular . Most granules are small and
regular. They alternate with larger round droplets
having a homogeneous eosinophilic appearance
and a stronger PAS positivity.
• The pattern of growth is ill-defined and
Alveolar soft part sarcoma
• Site- thigh and leg, oral cavity and pharynx
mediastinum ,stomach, retroperitoneum,
orbit, bladder, uterus, and vagina.
• Most patients are young females.
• Grossly, the tumors are well circumscribed,
usually large, moderately firm, and gray or
yellowish. Areas of necrosis or hemorrhage.
• Microscopically, the tumor cells are separated by
fibrous tissue into well-defined nests.
Detachment of the central cells results in a typical
alveolar pattern . The individual cells are large
and have vesicular nuclei, prominent nucleoli,
and a granular cytoplasm. Mitoses are
• PAS stain sometimes demonstrates the presence
of diastase-resistant intracytoplasmic needle-like
Alveolar soft part sarcoma
The tumor is multinodular, relatively well
circumscribed, and embedded within skeletal
Typical microscopic appearance of alveolar
soft part sarcoma. Note the lack of mitoses
Clear cell sarcoma of tendons and
• This malignant tumor arises chiefly from large tendons and aponeuroses
of the extremities.
• Most of the patients are young adults, and there is a male predominance.
• Grossly, the tumors are firm, well circumscribed, and gray or white, and
are cut with a gritty sensation .
• Microscopically, solid nests and fascicles of pale fusiform or cuboidal cells
are present . The nucleoli are large and deeply basophilic. Multinucleated
giant cells are often seen. Abundant extracellular and intracellular iron is
present. In many of the cases the tumor cells also contain cytoplasmic
• Strongly suggesting that this neoplasm is of neuroectodermal derivation
and that it represents a peculiar type of malignant melanoma of soft
• Immunoreactivity for S-100 protein, HMB-45, Leu7, NSE, and vimentin.
of clear cell sarcoma (malignant
melanoma of soft parts
Clear cell sarcoma of soft parts. Note the
fascicular pattern of growth and the
Extraskeletal Ewing sarcoma/PNET
Tumors morphologically indistinguishable from Ewing sarcoma of
the skeletal system can present as soft tissue masses.
In some cases, they simply represent soft tissue extensions of
tumor originating in the underlying bone.
Most of the patients are adolescents or young adults, and the
usual sites of involvement are the deep soft tissues of the lower
extremity and paravertebral region.
Microscopically, like their skeletal counterpart, they are composed
of uniform small, round, or oval cells containing cytoplasmic
glycogen and sometimes arranged in a ‘peritheliomatous’ pattern .
Extraskeletal Ewing sarcoma/PNET. The tumor is
extremely cellular, with hardly any intervening
stroma. Some tumor cells are attached to a vessel
wall in a pseudorosette arrangement
Phosphaturic mesenchymal tumor
• Association between tumors of soft tissue and bone and osteomalacia or
• The syndrome results from tumor production of a renal phosphaturic
substance that depletes total-body phosphates by inhibiting tubular
reabsorption of phosphate.
• It is characterized biochemically by hypophosphatemia, renal phosphate
wasting, and decreased serum 1,25-dihydroxyvitamin D3 levels.
• The soft tissue tumors associated with this complication have shown an
admixture of microscopic features.
• Microscopy- characteristic feature has been the association of
hemangiopericytoma-like areas and osteoclast-like giant cells, with or
without foci of osseous and cartilaginous metaplasia. A ‘grungy’ calcified
matrix is said to be particularly distinctive
• Immunohistochemically, they usually express fibroblastic growth factor-23
Phosphaturic mesenchymal tumor
A, This area has a hemangiopericytoma-like quality.
B, In this area from the same tumor, there is chondroid
differentiation and a scattering of osteoclast-like giant cells.
Pleomorphic hyalinizing angiectatic
tumor of soft parts (PHAT)
• This tumor type can simulate schwannoma by virtue of the angiectatic
vasculature, the presence of hemosiderin-laden macrophages, and the
occurrence of a spindle cell component with scattered bizarre nuclear
forms but practically no mitotic activity .
• Two diagnostic clues are represented by the nuclear pseudoinclusions and
the fact that many of the bizarre cells are embedded within a fibrinous
material surrounding the angiectatic vessels.
• CD34 is focally positive and S-100 protein is negative..
• Fig. 25.218
• Cytogenetically, supernumerary ring chromosomes have been found,
linking PHAT with other low-grade mesenchymal malignancies, such as
dermatofibrosarcoma protuberans, parosteal osteosarcoma, and well-
differentiated liposarcoma. Local recurrences
Pleomorphic hyalinizing angiectatic tumor of soft
parts. The pleomorphic tumor cells surround dilated