"Metastatic malignant nodular hidradenoma": A rare case report with review of literature

Malignant nodular hidradenoma (MNH) also known as hidradenocarcinoma is very rare adnexal tumor with exceedingly low incidence of 0.001%. The recognition is very important because eccrine carcinomas have potential of local destruction and distant metastasis. Given the relative paucity of published data with only just over 50 case reports and small case series, there is little information available on the natural history and appropriate management for this disease. It has been reported most frequently in the head and neck and rarely on the extremities. There is no consensus treatment for metastatic hidradenocarcinoma since it is a rare and aggressive tumor. We report a rare case of MNH in a 70-year-old female presented with inguinal lymphadenopathy and discuss cytological findings and histopathological features with review of literature. Adnexal tumors need thorough histopathological analysis to conclude their biological behavior. This study will highlight the importance of appropriate wide excision of primary adnexal tumors and thereby preventing metastatic presentations in future.