Poroma

For a year, a 35-year-old man had an asymptomatic, slowly growing, semifirm nodule on the lateral aspect of his hand. He was concerned that it was malignant. Benjamin Barankin, MD, of Edmonton, Alberta, made the clinical diagnosis of a poroma—a benign sweat gland tumor composed of epithelial cells that show ductal differentiation.

Poromas can be of either apocrine or eccrine origin. Historically, they were considered mainly eccrine in origin, hence the common term “eccrine poroma.”

The malignant counterpart of a poroma is a porocarcinoma. Pigmented and multiple poromas are uncommon; infrequently, a poroma may arise in a nevus sebaceus.¹ A poroma usually manifests as a solitary, asymptomatic papule or nodule that affects the side of the foot and sole or the hand in adults.

Occasionally, the diagnosis is made based on the clinical presentation; however, because poromas are not clinically distinctive, biopsy is often necessary. The treatment is complete surgical excision, which is curative. This patient was referred to a hand surgeon.