Giant cell tumor (GCT) of bone most commonly occurs at which site, and what is the defining histological feature?

• A Diaphysis of long bones; storiform pattern of spindle cells
• B Metaphysis of long bones in children; osteoblastic lacunae with giant cells
• C Flat bones; palisading arrangement of spindle cells with giant cells
• D Epiphysis of long bones after skeletal maturity; multinucleate giant cells with uniform oval mononuclear stromal cells ✓

Explanation

GCT characteristically arises at the epiphysis of long bones after skeletal maturity (closed physis) — distal femur is the commonest site, followed by proximal tibia and distal radius. Histologically, it shows multinucleate osteoclast-like giant cells (with >20 nuclei per cell) uniformly distributed among oval mononuclear stromal cells that are the true neoplastic component; the giant cells are reactive. The pathognomonic feature is uniformity — giant cells are evenly distributed, distinguishing GCT from other giant-cell-containing lesions like aneurysmal bone cyst. Denosumab (RANK-L inhibitor) targets the stromal cell RANK-L/OPG axis and is now used for unresectable/recurrent GCT.

Reference: Maheshwari Essential Orthopaedics, 6th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.