Abstract
A 52-year-old woman had noticed a slowly growing subcutaneous tumor in the right axilla for about 30 years. At the first clinical examination, a hard subcutaneous mass, measuring about 3cm in diameter, was found adhered to the right axillary skin. Beneath this, another mass approximately the size of an index finger tip was detected continuous with this tumor. Both masses were resected under local anesthesia. Histopathological examination revealed that the tumor consisted of a slit-like duct representing a biphasic structure composed of cuboidal epithelial cells and muscle epithelial cells, and stroma with abundant mucous and collagen fibers. Normal breast structures were found around this tumor. Therefore, we diagnosed this case as a fibroadenoma that developed from the axillary accessory breast. Whenever a subcutaneous tumor is found on an axillar lesion, benign and malignant tumors arising from the accessory breast should be considered.Skin Research, 12: 336-338, 2013
