Syringomatous tumor of the nipple.

The authors describe two women with locally infiltrative neoplasms of the nipple that exhibited sweat duct differentiation. The findings are compared with those previously recorded for syringomatous adenoma of the nipple. The patients presented with firm, subareolar nodules. Nests, cords, and ducts composed of cytologically uniform squamous cells were dispersed throughout the dermis and also involved subcutaneous tissue and adjacent breast parenchyma. Small keratocysts formed a minor component of the lesions. Additional observations in the present study included connections between tumor and epidermis; distinctive fibrous stroma; sparse mitotic figures; perineural invasion; carcinoembryomic antigen in luminal content and periluminal cytoplasm; tumor cells that contained S-100 protein; and Langerhans' cells within neoplastic cellular aggregates. Neither of the lesions had recurred after follow-up of 9 and 12 months. The foregoing neoplasms of the nipple appear to be part of a family of microscopically similar tumors that have a predilection for the face, breast and possibly the axilla and salivary tissue. Although capable of local recurrence, syringomatous tumors of the nipple and related lesions at other sites have not been reported to metastasize.