Breast carcinoma with stromal multinucleated giant cells--a light microscopic, histochemical and ultrastructural study.

A rare form of infiltrating ductal carcinoma of the breast containing numerous benign stromal multinucleated giant cells (MNGC) is described. Giant cell tumours of the breast are usually the result of stromal metaplasia or fusion of malignant cells or occur as extraskeletal giant cell tumours. Benign multinucleated cells in breast carcinoma, however, are a very unusual phenomenon and have been said to arise from the fusion of mononuclear cells, in response to increased vascularity. The present investigation by light and electron microscopy, in part, supports an origin for the multinucleated giant cells from mononuclear cells, but immunohistochemistry surprisingly failed to confirm this observation. Also, the formation of the multinucleated giant cells did not show any direct relationship with tumour vascularity.