Poroid hidradenoma of the scalp.

Poroid hidradenoma has both features of hidradenoma and poroma. The histological hidradenoma framework consisting of solid and cystic components, and the presence of poroid and cuticular cells resembling a poroid neoplasm. Despite transforming into malignant neoplasm only in < 1% of cases, its histological characteristics may resemble those of malignant neoplasms. Although the risk of malignant transformation is very low, surgical excision is recommended to prevent growth and/or recurrence. To date, very few cases of poroid hidradenoma have been reported in the literature. Herein, we present a case of poroid hidradenoma on the scalp of a 74-year-old woman.