Glycogen-rich clear cell carcinoma of the breast. An autopsy case.

An autopsy case of glycogen-rich clear cell carcinoma (GRCCC) which arose in the right breast of a 72-year-old woman is reported. Light microscopic examination of the small finger-tip-sized tumor revealed solid alveolar proliferation of clear cells containing abundant glycogen. Immunohistochemically, most of the clear tumor cells were stained for epithelial membrane antigen (EMA) and alpha-lactalbumin, whereas a few eosinophilic tumor cells were positive for S-100 protein, EMA and actin. Electron microscopically, aggregates of glycogen particles, numerous empty glycogen lakes, microvilli, tight junctions and basal lamina were identified. Autopsy disclosed marked metastases to the liver, lung, adrenal, skin and lymph nodes. Primary breast cancer was confirmed by exclusion of a primary at any other site. It is suggested that although rare, GRCCC of the breast is as aggressive as usual invasive ductal carcinoma, and is associated with severe nodal and blood-borne metastases, followed by death.