89
Osteochondroma
Kevin D. Plancher and Michael Bothwell
History and Clinical Presentation
A 14-year-old boy presents with a growth on the end of his index finger. He notes that it has slowly been getting larger. He has had the growth for 3 years, but recently became concerned following his mother’s battle with cancer. It is not painful unless he hits it hard on something. The patient has no history of cancer.
Physical Examination
A cartilaginous growth is seen on the end of the index finger. The mass projects from the volar surface. There are no other growths on either of the patient’s hand.
Diagnostic Studies
Radiographs reveal a peripheral bone projection or growth with flaring of the metaphysic of the bone (Fig. 89–1). There is also a communication of the cortical and cancellous bone, which may contain focal areas of calcification at the site of the osteochondroma. Covering the top of the tumor is a thin, sclerotic area of cartilaginous cells.
Histologically, the surface of the lesion reveals a thin smooth, translucent, bluish cartilaginous cap. The lesion may be pedunculated or sessile. When pedunculated the lesion projects away from its nearest joint (Fig. 89–2).
Differential Diagnosis
Inclusion cysts
Giant cell tumors
Chondrosarcoma
Diagnosis
Osteochondroma is the most common benign tumor of bone. It originates in the metaphysis of long bones and may have multiple foci. The tumor typically appears in the second decade and has a male predominance of 1.7 to 1.0. In the upper extremity it is commonly located in the proximal humerus as well as the distal radius and ulna (Fig. 89–3).
