Presentation on Benign Bone Forming Tumors

1. BENIGN BONE
FORMING TUMORS
PRESENTER : DR. BIJAY MEHTA
MODERATOR : DR. LAXMI KANTA SHARMA

2. CONTENTS
•Definition
•Classification
•Osteoid Osteoma
•Osteoblastoma
•Osteoma
•Bone Island
•Summary

3. Definition
• Characterized by the formation of osteoid or mature bone directly by the tumor
cells
•Osteochondroma is the commonest benign bone tumor(30-35 %)
•Osteoid Osteoma is commonest benign bone forming tumor.

4. Bone Forming Tumors : Classification
Benign
◦ Osteoid Osteoma
◦ Osteoblastoma
◦ Osteoma
◦ Enostosis (Bone Island)
Malignant
◦ Osteosarcoma

5. OSTEOID OSTEOMA
•First described by Jaffe in 1935
•A small ,discrete ,painful benign neoplasm
•Age -mostly young men,2nd -3rd decade
•Male :female =3:1
•Relatively Common-
• 4% of all primary bone tumors
• 10% of all benign bone lesions

6. Cortical or cancellous bone.
• Lower extremity(>50%) :Prox . femur >tibia
• Spine 10-15%-mostly in post elements
• thoracic>lumbar >cervical >sacral
• Hand-scaphoid and prox phalynx,
• Foot <5% -talar neck
OSTEOID OSTEOMA : SITE

7. Pathoanatomy
Nidus –central nodule of woven
bone and osteoid with
osteoblastic rimming
Reactive zone -area of thickened
bone and fibrovascular tissue

8. OSTEOID OSTEOMA: CLINICAL FEATURES
1.Pain – constant and progressive ,worse at night and is relieved by aspirin or
other NSAIDS
2. Swelling, stiffness, and contracture –if near joint
3. Scoliosis - When the lesion is in a vertebra
4. Growth disturbance may be present

9. IMAGING
•X-ray- sufficient to make the diagnosis -intensely
reactive bone around radiolucent nidus of size
<1.5 cm
•Computed Tomography (CT) is the best technique
to identify the nidus and confirm the diagnosis.
•Magnetic Resonance Imaging (MRI) studies –not
done usually
•Bone scan
• Intense hot area of focal uptake at the nidus and low
uptake in reactive zone -“double density sign “

10. OSTEOID OSTEOMA : HISTOLOGY
•Biopsy -rarely is needed to confirm the diagnosis
• Fibrovascular tissue with immature bony
trabeculae that are rimmed by prominent
osteoblasts.
• The appearance is similar to that of an
osteoblastoma with the exception that
osteoblastomas are larger.
• Nidus is sharply demarcated from surrounding
normal bone
• No nuclear atypia.
• Occasional osteoclasts and giant cells seen but
no aggressive features

11. OSTEOID OSTEOMA : DIFFERENTIAL DIAGNOSIS
•Cortical Osteoid Osteoma
• Cortical Bone Abscess
• Stress Fracture
• Intracortical Osteosarcoma
•Medullary Osteoid Osteoma
• Brodie’s Abscess
• Bone Island

12. OSTEOID OSTEOMA : TREATMENT
•Options available
• Medical management ,
• Percutaneous radiofrequency ablation,
• Open surgical procedures and
• MRI guided therapy

13. Medical Management
•NSAIDs-
• Symptoms adequately controlled and patient is willing to undergo
long-term medical management, NSAIDS can be used as the
definitive treatment.
• Spontaneous healing of the lesion within 3 to 4 years(50 %)
• Also indicated for spinal lesions without scoliosis .
• Fingertip lesions donot respond well.

14. •Lesions of the pelvis or long bones of the extremities.
Involves a CT-guided core needle biopsy . Radiofrequency
electrode is inserted through the canula of the biopsy needle.
•The temperature at the tip is increased to 90° C for 6
minutes.(produce 1 cm zone of necrosis)
•Recurrence rate-< 10%.
•Contraindicated
• vertebral lesions or
• lesions of the small bones of the hands or feet
Percutaneous Radiofrequency Ablation

15. Surgical Management
•Removal of the entire nidus.
•2 methods –
• curettage or en bloc resection (low
recurrence but rarely indicated for in the long
bones )
• burr-down technique- identifying the
nidus intraoperatively with fluoroscopy
and using a power burr to remove the
sclerotic bone directly over the nidus.

16. •The nidus is removed using curettes and sent for pathologic
examination.
•The cavity is treated again with the power burr to ensure that
the entire nidus has been removed. Only a minimal amount of
surrounding reactive bone is removed,
•Recurrence <10%.

17. Magnetic Resonance guided Focused
Ultrasound (MRgFUS)
•Ablation technique-
• Ultrasound waves are focused on the osteoid osteoma. When high-intensity waves
are focused on a single point, considerable heat can be generated.
•MRI is used for both lesion localization and temperature monitoring.

18. OSTEOBLASTOMA
•Benign Tumor of osteoblasts producing osteoid and woven bone
•Similar in appearance to an osteoid osteoma , but are larger in size
(So called Giant osteoid osteoma)
•1% of all primary bone tumors and 3% of all benign bone lesions
•Seen commonly in age group 10- 30 yrs
•Male : Female – 2: 1

19. •Commonly seen in spine
• About 30-40% of all osteoblastomas are confined to spine
• mainly in the posterior elements including the arch and spinous
processes
•Mandible
•Long tubular Bones: Lower limb > Upper limb
OSTEOBLASTOMA: SITES

20. OSTEOBLASTOMA: CLINICAL FEATURES
•Usually presents with pain- dull, localized pain, with a median
duration of symptoms of 6 months before they present for treatment
•Patients with vertebral lesions present with features of nerve root
compression and neurologic deficits ranging from weakness to
paralysis
•Tenderness may be present
•Scoliosis may be a finding

21. OSTEOBLASTOMA : IMAGING
•Four distinctive types of based on the radiographic findings –
• a)The lesion may be almost identical to osteoid osteoma,
although much larger (usually >2 cm in diameter).
• exhibits less reactive sclerosis than osteoid osteoma
• b)Osteoblastoma may also appear as a blow-out expansive
lesion similar to an aneurysmal bone cyst,
• with small radioopacities in the center.
• This pattern is particularly common in tumors involving
the spine

22. OSTEOBLASTOMA : IMAGING
•(c) The tumor may occasionally appear as an aggressive lesion, simulating a
malignant neoplasm.
• Many of the so-called aggressive osteoblastomas belong to this group.
•(d) Exceptionally rare, osteoblastoma is juxtacortical (periosteal) in
location,
• These lesions generally lack perifocal bone sclerosis

23. OSTEOBLASTOMA : IMAGING
•CT
• Areas of calcifications and ossifications within the lesion as well as cortical
destruction and soft tissue extension, are well delineated on CT sections
•MRI
• Non specific and often overestimate the lesion
• Hypo to isointense lesions are seen
• Highly vascular tumor-so contrast enhancement is seen
•Bone Scan- demonstrates intense focal accumulation of bone-seeking
radiopharmaceutical agents –similar to other neoplasms

24. OSTEOBLASTOMA : HISTOLOGY
•Similar to osteoid osteoma
•Irregular trabeculae of woven bone
(osteoid) surrounded by densely arranged
osteoblasts.
•Well demarcated from surrounding tissues
•Osteoblasts line up periphery of
trabeculae(Osteoblastic Rimming)

25. OSTEOBLASTOMA : DIFFERENTIAL DIAGNOSES
•Osteoid Osteoma
•Aneurysmal Bone Cyst
•Osteosarcoma
•Bone Abscess

26. OSTEOBLASTOMA: TREATMENT
•In majority of the case – Intralesional curettage with radiofrequency
ablation
•En-block resection may be required
•Pre-operative embolization should be considered in cases of larger
lesions to reduce intraoperative hemorrage

27. Osteoid osteoma vs osteoblastoma

29. OSTEOMA
•Rare, Slow-growing lesion consisting of well-differentiated mature bone tissue
with a predominantly lamellar structure
•Protruding mass of dense periosteal intramembranous bone on surface of host
bone
•commonly arising in the frontal and ethmoid sinuses (approximately 75% of
cases)

30. •It may also occur on the –
• surface of the outer table of the calvaria (“ivory exostosis”),
• the bones of the jaw and, –
• rarely, on the surface of the flat bones and the long and short
tubular bones

31. Clinical Features
•4th to 5th decade
•Usually asymptomatic ,
•If symptoms -Present with ENT issues -Sinusitis
•Long bone, tubular bone osteomas are mostly silent.
• May be associated with
• Familial adenomatous polyposis syndrome (Gardner syndrome)
• Tuberous sclerosis
•Osteomas of the soft tissues (so-called osseous choristomas) are rare
occurrences

32. Imaging
•Conventional radiography is the basis for the
diagnosis of osteoma.
• Radiographs typically show a dense, ivory-like
sclerotic mass with sharply demarcated borders
attached to the bone.
•Long bone, tubular bone, flat bone osteomas are
often termed parosteal for their lack of cotical
invasion.
•Most parosteal lesions measure 1 to 4 cm in
diameter

33. Histology
•Histologically, it can be of cancellous and
compact type
•The cancellous (or trabecular, or spongy)
osteoma reveals a cancellous, trabecular
architecture.
•A compact osteoma usually exhibits empty
osteocyte lacunae in varying numbers

34. Differential Diagnosis
•Periosteal Osteoblastoma
•Melorheostosis
•Ossified Periosteal Lipoma
•Parosteal Osteosarcoma
•Sessile Osteochondroma

35. Treatment
•Observation
•Requires Excision only if cause complications like Mucocele formation or mass
effect

36. BONE ISLAND
•Also known as Enostosis
•Benign Lesions of cancellous bone which present as small focus of
compact bone within a cancellous bone
•Usually asymptomatic and are incidental finding

37. •Although previously considered as a benign bone tumour, it is
unclear whether it is developmental abnormality or a neoplastic
process
•Femur and Pelvis are common sites – although any bone can be
involved
•It is of importance because of its more aggressive differentials such
as osteoblastic metastasis , Low grade osteosarcomas
•Osteopoikilosis- A condition with multiple bone island throughout
the skeleton

38. Imaging
Xray- seen as small round or oval foci of dense
bone within the medullary space
• commonly oriented with the long axis of the bone
parallel to the cortex.
• Highly distinctive for this lesion are radiating bony
streaks, referred to as “thorny radiation” or
“pseudopodia”
•No bony destruction or Periosteal Reactions
•range in size from 1 mm to 2 cms
•Giant bone islands are the ones greater than 2 cms
is diameter

39. • CT -appears as a low attenuation focus exhibiting its characteristic brush
borders
•MRI - exhibits the low signal intensity characteristics of cortical bone
•Bone Scan shows no or mildly increased uptake – markedly increased uptakes
should raise suspicion of other diagnoses

40. Bone Island : Histology
•Appear as a focus of compact
(cortical) bone in the medullary
canal
•shows thorn-like, thickened
trabeculae radiating from the
lesion and merging with the
surrounding trabeculae of the
normal bone.

41. Differential Diagnoses
•Osteoblastic Metastases
•Osteoma
•Osteoid Osteoma
•Sclerosing Osteosarcoma
•Sclerotic Myeloma
•Osteoblastoma

42. Treatment
•Usually observation with serial radiograph will suffice
•Consider biopsy if there is –
• Pain
• Lesion grows 50%in one year or 25% in six months

43. Take Home Message
•Osteoid Osteoma and Osteoblastoma are two important benign bone forming
tumors.
•Histologically, both of them are similar except Osteoblastoma is larger in size.
•Clinically, Osteoid Osteoma presents with pain, which is worse at night and is
relieved by aspirin or NSAIDs.
•While Osteoid Osteoma can be managed medically or with miniinvasive
techniques Osteoblastoma need surgical treatment.
•Aggressive Osteoblastoma needs to be differentiated from osteosarcomas.

44. References :
•Campbell’s Operative Orthopaedics, 13th Edition
•Apley and Solomon’s System of Orthopaedics and Trauma, 10th Edition
•Miller’s Review of Orthopaedics, 8th Edition
•Parmeggiani A, Martella C, Ceccarelli L, Miceli M, Spinnato P, Facchini G. Osteoid
osteoma: which is the best mininvasive treatment option? Eur J Orthop Surg
Traumatol. 2021 Apr 11. doi: 10.1007/s00590-021-02946-w. Epub ahead of print.
PMID: 33839926.
•Orthopedic Oncology Course , James C. Wittig, MD

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46. Thank You