Abstract
Hidradenocarcinoma is a rare malignant adnexal tumour which arises from the intradermal duct of eccrine sweat glands. The head and neck are the most common sites of hidradenocarcinoma, but rarely it can occur on the extremities. As it is an aggressive tumour, regional lymph nodes and distant viscera are the most common sites of metastasis. Diagnosis is confirmed by histopathology and immunohistochemistry. Hidradenocarcinoma should be differentiated from benign and malignant adnexal tumours. Being an aggressive and rare tumour, no uniform treatment guidelines have been documented so far for metastatic hidradenocarcinoma. Wide local excision is the mainstay of the treatment, but because of high local recurrence, radiotherapy in a dose of 50Gy-70Gy and/or 5-fluorouracil and capecitabine-based combination chemotherapy may be given to further improve local control. Other treatment strategies are targeted therapies like trastuzumab, EGFR inhibitors, PI3K/Akt/mTOR pathway inhibitors, hormonal agents like antiandrogens, electrochemotherapy, or clinical trials.