Adenocarcinoma with signet ring cells of the axilla: two case reports and review of the literature.

Adenocarcinoma with signet ring cells (ASRC) is a rare skin neoplasm whose histology shows a solid tumor intermingled with signet ring cells in variable numbers. There have been only ten reported cases. All were elderly males affected on the eyelids except for a single case in the axilla. Two new patients with ASRC of the axilla are described. In both of them, immunohistochemical studies revealed neoplastic cells that had differentiated toward apocrine glands. These are the second and third reported cases of ASRC in the axilla, one of them is the first ASRC case in a female. It seemed that the apocrine sweat gland or aberrant breast tissue in the axilla were possible origins of these tumors.