Malignant Hidradenocarcinoma in the Lower Extremity: A Case Report of a Rare Tumor.

Malignant hidradenocarcinomas are rare soft tissue tumors of sweat gland origin. We present the case of a soft tissue, fungating tumor of 15 years' duration of the medial ankle in an 85-year-old male that exhibited malignant features clinically and radiographically. Subsequent punch biopsy revealed a diagnosis of malignant hidradenocarcinoma. Given the risk of recurrence and the poor radiation and chemotherapy options, the patient initially decided to leave the lesion untreated. However, he soon developed lower extremity cellulitis from the exposed lesion and decided to have the tumor excised, eliminating the source of the infection. In the present case study, we discuss the etiology, clinical and radiographic characteristics, and treatment options for this rare lesion. At the 18-month follow-up visit, he had had no recurrence of the lesion.