CARCINOSARCOMA ARISING IN ECCRINE SPIRADENOMA OF THE BREAST - REPORT OF A CASE AND REVIEW OF THE LITERATURE

Although the vast majority of eccrine spiradenomas behave in a benign fashion, 23 cases of malignant transformation have been reported to da te. We describe a unique example of malignant eccrine spiradenoma that arose in the right breast of a 68-year-old woman. The quiescent mass, which was present for approximately 50 years, experienced sudden enla rgement with erythematous changes of the overlying skin and nipple dis charge. Microscopically, the tumor showed the typical features of an e ccrine spiradenoma with areas of adenocarcinoma, squamous cell carcino ma, and sarcoma. The sarcomatous component consisted of rhabdomyosarco ma and osteosarcoma. The immunoperoxidase staining revealed p53 protei n expression only in the carcinomatous and sarcomatous components. Thi s suggests that accumulation of p53 protein may be an important event in the malignant transformation of spiradenomas. Because of its locati on and biphasic nature, this malignant eccrine spiradenoma should be d istinguished from metaplastic breast carcinoma. To our knowledge, this represents the first carcinosarcomatous transformation of eccrine spi radenoma in the breast. This case led us to conclude that breast tissu e, which often undergoes apocrine metaplasia and gives rise to apocrin e neoplasms, is also capable of originating benign and malignant tumor s with eccrine sweat duct phenotype.