Poroid hidradenoma in the hand: A case report and systematic review.

Poroid hidradenoma (PH) is a rare benign neoplasm of the skin appendages. There are currently no guidelines for its management, and little information available regarding the natural history, treatment options, or outcomes. Systematic literature review identified 19 cases of isolated PH. Mean age at presentation was 54 years. Male to female ratio was 3:1, and the majority of cases were in the head and neck region. One-third of lesions were painful or tender. Sizes varied from 0.11 × 0.9 × 0.2 cm (digit) to 6 cm (presternal region). Twelve cases were treated by surgical excision, while the remainder were biopsy specimens. Follow-up was reported in five cases, with a median follow-up of 1 year. No cases of local invasion or spread have been reported, although there was one case of possible recurrence identified 8 years after surgical excision. The presented case is the first to identify a PH on the hand, represents the smallest lesion to date, and was successfully treated by excision. We suggest that PHs be treated by excision and followed up for 6 to 12 months. Given one case of potential (but unconfirmed) recurrence, and no report of malignant transformation, we suggest that narrow margins may be appropriate.