SYRINGOCYSTADENOMA PAPILLIFERUM OF THE MALE BREAST

A 39-year-old man presented with a 2-cm, mildly tender mass in the rig ht breast of many years' duration. Microscopic examination showed a sy ringocystadenoma papilliferum. Because of its location in the breast, we studied the lesion for immunohistochemical markers for apocrine dif ferentiation. Gross cystic disease fluid protein-15 (GCDFP-15) stainin g yielded negative results in the cystic luminal epithelial cells, whe reas GCDFP-15 and lysozyme staining yielded strongly positive results in the epithelial cells of adjacent tubular apocrine glands. Focal str ong lysozyme positivity was seen in the cystic luminal epithelial cell s. These findings do not support apocrine differentiation in this case , despite its location in the breast, an organ rich in specialized apo crine (lactiferous) elands. To our knowledge, this represents the firs t reported case of syringocystadenoma papilliferum of the male breast. We present the clinical and pathologic features of this unusual case and a review of the literature.