Cavernous lymphangioma of the breast: case report with electron microscopic and immunohistochemical investigations.

A rare case of cavernous lymphangioma of the breast in a 16-year-old Japanese girl was investigated by light and electron microscopies, and immunohistochemistry. The patient, who had a soft breast tumor measuring 16 x 14 cm, had undergone a tumorectomy two years after she noticed the tumor. Histologically, the tumor was composed of numerous narrow spaces containing amorphous fluid lined with a monolayer of endothelial cells. Abundant collagen fibers and numerous fibroblasts were found beneath the endothelium. Histological findings confirmed a diagnosis of lymphangioma of the breast. Immunohistochemically, the endothelium showed negative immunoreaction for factor VIII-related antigen, but the discontinuous basal lamina was positive for laminin. Ultrastructurally, numerous microfilaments and pinocytotic vesicles were found in the cytoplasm of the endothelial cells, and intermediate junctions were recognized between adjacent cells. In addition, a discontinuous basal lamina was seen beneath the endothelium. Electron microscopic and immunohistochemical investigations are thus useful in confirming a diagnosis of cavernous lymphangioma of the breast.