1. Beingn bone tumours

2. • Bone forming tumours:
1. Bone island
2. Osteoid osteoma
3. Osteoblastoma
• Cartilage forming tumour
1. Chondroma
2. Chondroblastoma
3. Chondromyxoid fibroma
4. osteochondroma

3. • Fibrous tumours
1. Fibrous cortical defect
2. Non ossifying fibroma

4. Bone island ( aka enostosis)
• Single/multiple
• Always medullary in location
• Normal compact lamellar bone
• Uniformly dense , round/oval lesion
• Chr radiating thorn like spicules
• Usually <15mm , can be as large as 4cm
• Periosteal new bone reaction/ cortical expansion donot
occur
• Normally bone island donot show increased uptake on
bone scan
• In patients with breast- or prostate cancer a bone island
can be mistaken for an osteoblastic metastasis

7. Osteoid Osteoma
• 20- 30 yrs
• M:F=3:1
• Intermittent bone pain of several wks/ mnths
duration occuring esp at night with dramatic
releif by aspirin
• Diaphysis of long bones are the site of
predilection esp at proximal end of femur and
tibia
• Spine usually involves neural arch and not the
vertebral body

8. Imaging features
• Round/ oval area of radiolucency with a sclerotic
margin
• Radiolucency contains a small dense opacity ( nidus)
• Usually prominent periosteal and endosteal reaction.
• Radionuclide scan shows intense focal area of
increased activity surrounded by less intense activity
from reactive sclerosis
• It must be differentiated from osteoblastoma, and
other causes of chronic cortical thickening eg chronic
sclerosing osteomyeltis.

12. Osteoblastoma
• Long h/o pain at night ( relief by aspirin is not a
feature)
• M=F
• <30 yrs
• Rare lesion
• MC affects spine( esp posterior arch and flat bones
• A typical osteoblastoma is larger than 2 cm, otherwise
it completely resembles osteoid osteoma.
• There is associated reactive sclerosis
• Calcification / ossification of osteoid tissue w/I tumour
may cause amorphous increase in density.

15. Chondroma
• single tumours are common
• MC in phalanges of hand and feet
• Although any bone maybe affected
• Risk of malignant transformation is greatest in
flat bones.

16. Imaging features:
• Well defined zone of radiolucency in medulla
• Small bones of hand and feet are likely to
expand and thin the overlying cortex
• Usually present with incidental fracture
• No destruction of cortex occurs
• No periosteal reaction occurs
• Flecks of calcification are frequenty present
w/I tumour

20. Juxtacortical chondroma
• arises at the surface of the bone.
• Scalloping of cortical bone is possible,
• no marrow involvement.
• It may be difficult to differentiate from a

22. Multiple enchondromas

24. Mafucci’s syndrome
• Multiple
enchondromas+
cavernous
hamenagiomas in
soft tissues

25. Chondroblastoma
• Relatively rare
• Epiphysis/apophysis
• Long h/o pain
• Well defined radiolucent oval lesion within
epiphysis is characterisitic
• Thin rim of sclerosis and cortical expansion is
seen
• Tumour can extend into metaphysis
• Stippled calcification occurs in 50% leisons
• No malignant transformation

29. Chondromyxoid fibroma
• 20-30 yrs
• M=F
• Usually occurs around the knee
• Occurs in metaphysis
• Radiolucent well defined eccentric
metaphysial lesion with surrounding sclerosis
• Cortex maybe expanded
• Calcification in lesion is extremely uncommon

31. Osteochondroma
• Osseous outgrowth from bony cortex
• Single>multiple
• When multiple k/a diaphyseal aclasia
• Very small risk of malignancy (chondrosarcoma)
• Arise mainly from tubular bones near metaphysis
• MC around knee , proximal end of humerus
• Sessile/pedunculated
• When pedunculated grows away from metaphysis
being directed towards diaphysis

32. • Bony protrusions covered by cartilaginous cap
• Growth in childhood takes place in the cap,
• A thick cartilaginous cap in an adult is
suspicious of chondrosarcoma.

37. Fibrous cortical defect
• Common lesion
• 2-15 yrs
• MC around knee ( sp distal posteromedial
femoral cortex)
• Blister like expansion of cortex with thin shell
of overlying bone
• Always sharply defined, maybe slightly
lobulated

38. • lucent intracortical defects
• outlined by a thin rim of sclerosis
• no involvement of the underlying medullary
cavity
• no periosteal reaction

40. Non ossifying fibroma
• Similar to FCD except that it is much larger
• 10-20yrs
• MC around knee ( esp distal end of femur)
• Eccentric well-defined lytic lesion with sclerotic
lobulated margin.
• Usually located around the knee in diaphysis or
meta/diaphysis and does not occur in hands, feet,
spine and flat bones.
• Found as incidental finding or presents with a fracture.
• The natural course is a sclerotic filling over time.