Malignant adnexal tumour of the shoulder—a rare case report

Malignant adnexal tumours are a very rare and highly aggressive primary skin neoplasms. Among them, malignant hidradenocarcinoma is a particularly aggressive tumour that arises from the intradermal duct of eccrine sweat glands. It more commonly arises de novo and rarely from a pre-existing hidradenoma. It is an aggressive tumour with regional lymph nodal and distant visceral metastasis. The prognosis is poor with a 5-year survival rate of 30%. Here, we present a 48-year-old female who came with a swelling over the left shoulder. On examination, it appeared to be chronic sebaceous cyst. The patient underwent wide local excision and the specimen was diagnosed as malignant nodular hidradenocarcinoma. Subsequent re-excision and sentinel lymph node biopsy was performed and margins were found to be microscopically negative for tumour. Based on the available literature wide local excision and sentinel lymph node biopsy appear to be the most common initial treatment plans.