Giant cell tumor Or Osteoclastoma

• Its so named because it contains multinucleated osteoclast like giant cells.

• It is benign but locally aggressive neoplasm occuring usually in 20 to 40 yrs age gr.

• Clinically located at the ends of long bone arising from epiphysis close to articular cartilage.Commonest site is knee(distal femur or proximal tibia) ,lower end of radius upper end of fibula

Gross appearance

• The tumor is eccentrically located at epiphyseal end of long bone.

• It is large well circumscribed reddish brown and frequently undergoes cystic degeneration.

• The mass remains covered by thin shell of subperiosteal bone.

• The cut surface is haemorrhagic necrotic honeycombed due to cystic degenrn.

Microscopic feature• The hallmark of GCT is presence of large no of

multinucleated giant cells which are scattered throughout the stromal mononuclear cells.

• These stromal cells are uniform plump spindle shaped or round to oval cells with numerous mitotic figures. These are real tumor cells belonging to mononuclaer family .

• Stroma has scanty collagen content ,rich vascularity and abundant macrophages. Somewhere areas of haemorrhage can be seen.

• Giant cells contain as many as hundred benign nuclei and are similar to osteoclasts