Benign and malignant nerve sheath tumors DR.N.PRIYADHARSHINI

1. BENIGN AND MALIGNANT NERVE
SHEATH TUMORS
DR.PRIYADHARSINI N
DEPARTMENT OF ORAL PATHOLOGY AND MICROBIOLOGY
SRM DENTAL COLLEGE , RAMAPURAM

2. Neurofibroma
 Common type of peripheral nerve neoplasm
 Arise from mixture of cells including perineural fibroblasts

3.  Can arise as solitary tumor or
neurofibromatosis
 Common in young adults
 Slow growing, soft painless lesion
varying in size from small nodule to
large masses

4.  Skin is the most common location
 Tongue and buccal mucosa common
in oral cavity
 Rarely arise within bone producing
well demarcated or poorly define
unilocular or multilocular
radiolucency.

5. Histopathology
 Well circumscribed within perineurium
 When occurs outside tend to blend
with adjacent connective tissues
 Composed of interlacing bundles of
spindle shaped cells exhibiting wavy
nuclei.

6.  Associated with delicate collagen and
variable myxoid matrix.
 Mast cells are numerous and are
diagnostic
 Sparsely distributed small axons
demonstrable by silver stains.
 IHC – S100 positive

7. Treatment
 Local surgical excision
 Recurrence is rare
 Should be evaluated for neurofibromatosis
 Malignant transformation possible.

8. Neurofibromatosis
 Common hereditary condition
 Eight forms have been recognized.
 Type I – von Recklinghausen disease
 Autosomal dominant trait
 Caused by NF1 gene mutation
responsible for tumor suppressor
protein neurofibromin

9. Clinical features
 Multiple neurofibromas that can occur
anywhere in body
 Clinical appearance can vary from
small papule to large soft nodules to
massive baggy pendulous masses
(elephantiasis neuromatosa) on skin

10.  Plexiform variant feels like a bag of
worms and considered
pathognomonic
 May be present at birth but appear
during puberty
 Accelerated growth seen in pregnancy

11.  Café au lait (coffee with milk )
pigmentation on skin
 Occur as yellow – tan to dark brown
macules that vary in diameter from 1 –
2 mm to several centimeters.
 They have a smooth edge “coast of
California”
 Coast of maine – Polyostotic fibrous
dysplasia

13.  Crowe sign – freckling of axilla

14.  Lisch nodules – translucent brown
pigmented spots on iris
 Hypertension, CNS tumors, short
stature, scoliosis, mental deficiency
are other complications

15. Oral manifestation
 Enlargement of fungiform papilla
 Only very few patient develop
intraoral neurofibromas
 Radiograph shows enlargement of
mandibular canal, increased bone
density, concavity of medial surface of
ramus

16.  The 7 clinical criteria used to diagnose NF1 are as follows: (the patient
should have two or more of following)
• Six or more café-au-lait spots or hyperpigmented macules greater than 5
mm in diameter in prepubertal children and greater than 15 mm
postpubertal
• Axillary or inguinal freckles (>2)
• Two or more typical neurofibromas or one plexiform neurofibroma
• Optic nerve glioma
• Two or more iris hamartomas (Lisch nodules), often identified only through
slit-lamp examination by an ophthalmologist
• Sphenoid dysplasia or typical long-bone abnormalities such as
pseudarthrosis
• First-degree relative (eg, mother, father, sister, brother) with NF1

17. Treatment
 Prevention and management of complications
 Facial neurofibromas can be removed using carbon di oxide laser and
dermabrasion
 Some may require cosmetic remodeling surgery
 Complication – neurofibrosarcoma , MPNST

18. Shwannoma (Neurilemoma)
 Schwannoma is a benign neural neoplasm of Schwann cell origin.
Relatively uncommon
 Schwannomatosis – multiple schwannomas
 Neurofibromatosis II – Bilateral schwannomas of auditory vestibular nerve

19. Clinical features
 Slow growing, encapsulated tumor arising in association with nerve trunk
 It pushes the nerve aside as it grows.
 Asymptomatic, tender in some instances
 Common in young and middle aged adults
 Range from a few millimeters to several centimeters in size

20.  Tongue is the most common location
 Occasionally arise within bone
 Pain and paresthesia present in intrabony tumors

21.  NF2 – caused my mutation of tumor suppressor gene NF2 which codes for
protein merlin
 Schwannomatosis related to mutation of SMARCB1 gene.

22. Histopathology
 Encapsulated tumor demonstrating
two microscopic patterns in varying
amounts
 Antoni A and Antoni B
 Streaming fascicles of spindle shaped
Schwann cells – Antoni A
 Form palisaded arrangement around
central acellular, eosinophilc areas
known as Verocay bodies.

23.  Verocay bodies contain reduplicated
basement membrane and cytoplasmic
processes.
 Antoni B – less cellular and less
organized and spindle cells randomy
arranged within loose, myxomatous
storma

24.  Degenerative changes seen in older tumors containing hemorrhage,
hemosiderin deposits, inflammation, fibrosis and nuclear atypia.
 Plexiform schwannoma another variant – multinodular plexiform growth
pattern. May be associated with NF2 or Shwannomatosis

25. Treatment
 Treated by surgical excision
 Malignant transformation is very rare

26. Malignant peripheral nerve sheath
tumor
 Malignant schwannoma, neurofibrosarcoma, neurogenic sarcoma
 Malignancy of peripheral nerve origin
 Common in proximal portion of extremities and trunk

27. Clinical and radiographic features
 Common in young adults.
 Mean age 29-36 years
 Enlarging mass that exhibits rapid growth.
 Associated pain or nerve deficit is common
 Oral tumors may occur anywhere
 Most common sites are mandible, lips and buccal mucosa
 Radiographic examination of intraosseous tumors reveal widening of
mandibular canal or mental foramen with or without irregular destruction
of surrounding bone

28. Histopathologic features
 Fascicles of atypical spindle shaped
cells resembling fibrosarcoma
 More irregular in shape with wavy or
comma shaped nuclei.
 Less cellular myxoid areas also may be
present.
 With some tumors heterologous
elements including skeletal muscle
differentiation (triton tumor),
cartilage, bone or glandular structures

29. Treatment
 Radical surgical excision along with radiation and chemotherapy.
 Prognosis is generally poor especially in patients with neurofibromatosis
type I