MACROSCOPIC FINDINGS
Received fresh, five irregular pieces of brown and pale grey soft tissue admixed with some cancellous bone 37x32x15mm in aggregate. One of the pale grey fragments shows an 8x5x3mm bright yellow area in the centre. A portion sent for cytogenetic studies. Representative sections after fixation. A-rusty brown fragments. B-fragments containing bright yellow area. P2.
MICROSCOPIC FINDINGS
Much of the material consists of densely cellular tissue with streams and whorls of spindle shaped cells, often with a prominent storiform growth pattern. Scattered through this population are numerous multinucleate giant cells and some haemosiderin laden macrophages are present.
There is no nuclear atypia. Occasional mitoses are present without atypical forms. In addition to this viable material, other fragments consist of necrotic debris surrounded by scar tissue with numerous haemosiderin laden macrophages and some spicules of degenerate bone.
The histologic features need correlation with radiologic and clinical findings but are most in keeping with non-ossifying fibroma (metaphyseal fibrous defect). The areas of necrosis and haemosiderin deposition most likely relate to the recent pathological fracture. Evidence of sarcoma is not seen.
DIAGNOSIS
Histologic features most in keeping with non-ossifying fibroma (metaphyseal fibrous defect).