A rare case of malignant adnexal tumor with sarcomatous transformation

Malignant eccrine tumors (MES, malignant cylindroma, and malignant spiradenocylindroma) are extremely rare and arise from pre-existing benign tumors. Due to the extreme rarity and close relation between these malignant tumors, most of the literature regarding these tumor entities is either in the form of reports of a single case or small series. Malignant eccrine tumors occur in patients over a wide age range of 34-92 years. We herein describe a case of a 68-year-old female who presented with a recently enlarging, nodular skin lesion over the inner aspect of left thigh that had been present for the last 10 years. The patient underwent wide local excision of the tumor. Microscopic examination revealed a neoplastic lesion comprising benign and malignant components. The sarcomatous component showed predominant spindle shaped cells which are pleomorphic with hyperchromatic large nuclei.. The benign component showed morphological features of Benign eccrine spiradenoma. No adjuvant treatment was administered. Careful identification and knowledge of histological variation are crucial to the correct diagnosis of this rare tumors.