Malignant hidradenoma: A report of two cases and review of the literature

Introduction: Malignant tumors of the sweat glands are very rare. Clear cell hidradenoma is a lesion with histopathological features resembling those of eccrine poroma and eccrine spiradenoma. The biological behavior of the tumor is aggressive, with local recurrences reported in more than 50% of the surgically-treated cases. Materials and Methods: Two patients are presented, the first with tumor in the right axillary region, the second with a recurrent tumor of the abdominal wall. The first patient underwent wide excision with clear margins and axillary lymph node dissection and the second patient underwent wide excision of the primary lesion and bilateral inguinal node dissection due to palpable nodes. Results: The patients had uneventful postoperative courses. No additional treatment was administered. However, sixteen months after surgery, patient 2 developed extensive and massive recurrence involving almost the whole abdominal wall. Although he had received several chemotherapeutic agents, the disease had a relentless course and the patient succumbed two and a half years following surgery. Conclusion: Malignant tumors of the sweat glands are very rare neoplasms with no discrete clinical characteristics. It is necessary to suspect any lesion which shows evidence of enlargement and to verify its status by histological evaluation. Additional resection is generally required, with at least 2-cm clear margins, since surgery is the only effective treatment.