Benign bone tumors

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thanks to radiologyassistant.nl
  1. Cartilage tumours.

 

  1. Enchondroma: 
  • Enchondromas may occur at any age but tend to manifest in people aged 10 to 40.
  • They are usually located within the medullary bone metaphyseal-diaphyseal region.
  • On x-ray, the tumor may appear as a lobulated calcified area within bone. If adjacent to the cortex, enchondromas show minor endosteal scalloping.
  • Enchondromas have increased uptake on a bone scan and thus create concern of cancer.
  • Multiple tumours may be found in Ollier’s disease (multiple enchondromas), Maffucci’s syndrome (multiple enchondromas with soft tissue haemangiomas) and with hereditary multiple exostoses (multiple osteochondromas). These syndromes have higher risk of progression into condrosarcoma.
  1. Fibrous tumours.

 

  1. Unicameral bone cyst (solitary bone cyst). These are most commonly found in the metaphysis of humerus and femur. Usually painless unless fracture supervenes. Treatment is by curettage and grafting, although drilling the cyst and injecting steroid is effective in smaller lesions. The development of a fracture often leads to spontaneous regression.
  2. Aneurysmal bone cyst (ABC).These can occur in any bone. They commonly involve the metaphyses of long bones and the vertebrae. They are eccentric, expansile, lytic lesions which expand and thin the cortex. The cyst is divided into spaces by a thin meshwork of trabeculae and is filled with blood. Treatment – meticulous curettage and grafting. 25% may recur.
  3. Non-ossifying fibroma (fibrous cortical defect)Occurs in young children but these have usually disappeared by the age of 11. They have a characteristic ‘soap-bubble’ appearance on X-ray with a well-defined zone of transition. Pathological fracture may occur.
  4. Fibrous dysplasia can affect one (monostotic) or several (polyostotic) bones. Rarely, it may be associated with brownish pigmented lesions on the skin over the site of the bony lesions in women with precocious puberty (Albright’s syndrome). Bone is replaced with a benign fibrous stroma containing areas of metaplastic bone. Pathological fracture is common. The radiographic appearance has been described as containing ‘bubbles and stripes’.
  5. Giant cell tumour constitutes approximately 5% of all bone tumours. Women : men (3:2),  peak incidence in the third decade. The distal femur, proximal tibia, distal radius and proximal humerus are the commonest sites. Presentation – swelling of one end of a bone. This may be painful, but is invariably so if a pathological fracture is present. Radiographs show an expanding, lytic lesion in the epiphysis and metaphysis which extends to, and can fracture, the subchondral bone. There is a narrow zone of transition. Extension may occur into the soft tissues, or into the adjacent joint, in which case an effusion may be present.

 

  1. Osseous tumours.

 

  1. Osteoid osteomaconstitutes about 10% of all benign bone tumours and 4% of all bone tumours. It occurs most commonly in the 2nd decade of life and is rare after the age of 30. Men > women. The commonest sites are the femur (27%), tibia (22%), posterior elements of the spine (10%), humerus, hand and fibula. The medial side of the femoral neck and the talus seem to be particular sites of predilection. The presentation is of persistent pain which is worse at night and often completely relieved by salicylates. The diagnosis is often delayed. An osteoid osteoma (or osteoblastoma) in the spine typically presents as a painful scoliosis. There may be swelling and point tendemess if the lesion is on the surface of a subcutaneous bone. Radiographs show a small, round, relatively radiolucent lesion (the nidus), measuring less than 1 cm across, surrounded by dense sclerosis (normal reactive bone). The lesion is usually situated in the cortex of diaphyseal bone but may be subperiosteal or medullary.
  2. Osteoblastoma is a rare tumour constituting only 3% of all benign bone tumours. It occurs at all ages but most commonly in the second or third decades of life. Men > women. It has a predilection for long bones, the posterior elements of the spine and the pelvis. It appears histologically similar to an osteoid osteoma but is usually larger (>1 cm) and can be locally aggressive. Pain is constant during the day but is less at night, not relieved by salicylates and NSAIDs than osteoid osteoma. Radiographs usually show an eccentric lesion in the diaphysis or metaphysis of a long bone. These may reach a considerable size. There is surrounding sclerosis, but its density is variable.

 



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