Apocrine carcinoma of the breast containing foam cells. An electron microscopic and immunohistological study.

The detailed light and electron microscopic and immunohistological features of an invasive apocrine carcinoma of the breast developing in a 78-year-old woman are presented. The stroma of the tumour contained non-neoplastic lipid-filled (foam) cells. To our knowledge, these cells have not been described before in invasive breast carcinoma. Their electron microscopic and immunohistological features confirm their histiocytic nature.