Eccrine spiradenoma of the nipple: Case report, differential diagnosis and literature review.

Eccrine spiradenoma is a rare lesion originating from eccrine sweat glands, with only few cases reported in breast tissue: we here describe for the first time, an eccrine spiradenoma arising in the nipple. An 84 year-old woman with a lesion enlarging her right nipple, showing ulcerations and eczema-like changes of the covering skin, was admitted to our hospital. Surgical excision of the central quadrant with nipple-areola complex was performed, followed by histopathological evaluation which revealed an adenoma with predominantly basaloid epithelial cells. The lesion was composed of tightly packed small and large groups of cells, arranged in diffuse alveolar/pseudorosette formations. The small cells expressed p63 and calponin, while a positive expression of CK7 and CD117 was detected in large cells. After careful and detailed examination, excluding various similar entities, a diagnosis of eccrine spiradenoma has been rendered. Although extremely rare, eccrine spiradenoma should be taken into account in the differential diagnosis of subcutaneous primary breast tumors.