Metastatic Hidradenocarcinoma: a Report of Two Rare Cases.

Hidradenocarcinoma is a rare malignant sweat gland tumour, characterized by a slow but aggressive course, with high rates of local recurrence and metastasis. Due to its rarity, histological criteria and therapeutic guidelines are poorly defined, posing a major challenge for clinicians and pathologists. To present two new cases of metastatic hidradenocarcinoma as well as a review of the literature. We describe two case studies and a review of the literature based on a search using the MEDLINE (PubMed) electronic database. The first patient was a 61-year-old woman with a perimamillary hidradenocarcinoma that arose from the malignant transformation of a benign childhood lesion and developed regional lymph node metastases after wide excision and adjuvant radiotherapy. The second patient was a 63-year-old man who developed cutaneous and renal metastases several years after the complete excision of a lumbar hidradenocarcinoma. As far as we can ascertain, kidney metastasis from hidradenocarcinoma has not previously been described. Most authors recommend wide excision as the treatment of choice for hidradenocarcinoma, however, optimal adjuvant therapy remains to be determined. Our cases add to the limited knowledge available, but high-quality studies to find new effective treatments are needed.