Squamoid eccrine ductal carcinoma.

We describe three cases of a distinctive cutaneous adnexal neoplasm showing features of eccrine ductal differentiation that were characterized by a prominent squamoid component. The tumours presented as solitary dermal nodules on the head and neck areas and the extremities in elderly patients. Histologically, they were characterized by a prominent squamous proliferation with atypia, keratinous cyst formation and squamous eddies which seemed to merge with areas showing eccrine ductal differentiation, including ductular formations in continuity with eccrine ductal epithelium. Clinical follow-up in one case showed multiple local recurrences over a period of 3 years despite complete surgical excision. Squamoid eccrine ductal carcinoma should be considered in the differential diagnosis of cutaneous adnexal neoplasms showing squamoid and ductal features of differentiation.