Recurrent atypical eccrine spiradenoma of the forehead

Eccrine spiradenoma is an uncommon but well recognized benign adnexal tumour of the eccrine sweat glands. It can appear at any age, but the highest rate of incidence is observed among young adults, without any sex predilection. The commonest clinical presentation is a solitary blue-red dermal or subcutaneous cystic nodule, ranging from 0.3 to 5 cm in diameter. Malignant transformation is a rare phenomenon, presenting as a rapidly enlarging nodule within a long-standing lesion. We report a case of eccrine spiradenoma in a thirty-six-year-old man who presented with a recurrent soft-tissue neoplasm of the forehead, with cytological atypia. The differential diagnosis of this tumour, as well as its possible malignant transformation, is discussed.