Giant cell tumour

Morphology of osteoclastoma: laboratory and biopsy findings…

Histologic pattern is one of:

• Many uniformly distributed osteoclast-like, multinucleated giant cells in a plump spindle cell background (mononuclear cell population)

[The neoplastic cell is the spindled stromal cell; the multinucleated cells are thought to arise from fusion of the spindle cells.]

There may be foci of necrosis, haemorrhage, hemosiderin or osteoid.

Macroscopic and radiologic appearances are distinctive (not pathognomonic):

• Imaging may reveal large lytic soap-bubble lesions; absent are stippling and calcifications.

• Classically lucency presentation epiphyseal in location (femur, tibia & radius) definition (though may extend to involve the metaphysis), subchondral and eccentrically located to long axis of bone.

• Cortical expansion and focal destruction may be observed, sometimes with extension into overlying soft tissues (20%).

Histologic features do not allow prediction of which tumours will recur or metastasize. A rare lesion is overtly malignant from the outset.

This biologic unpredictability complicates clinical management:

• Majority of tumours are localized and can be eradicated by curettage or conservative resections

• 40-60% recur locally

• 1-2% develop deceptively benign-looking metastases to the lungs

• ~10% develop obviously anaplastic metastases

Category: Orthopedics Notes , Pathology Notes