Infiltrating syringomatous adenoma of the nipple: a case report and 20-year retrospective review.

Infiltrating syringomatous adenomas are rare lesions of the nipple that were first described in 1983. The exact origin of these lesions is uncertain, although derivation from eccrine structures of the nipple has been postulated because the lesions are microscopically reminiscent of other tumors of eccrine origin, such as syringomatous carcinoma. The lesions are usually infiltrative, showing an expansile pattern of proliferation into adjacent tissues of the nipple and underlying breast. Involvement of the epidermis, however, has not been described. The lesions behave in a benign fashion, with no evidence of regional or distant metastasis in any of the reported cases. Complete local excision appears to be sufficient therapy, with only incompletely excised cases showing recurrence. We report an additional case of infiltrating syringomatous adenoma of the nipple and review the medical literature related to this lesion published in the 20 years since its initial description.