A Growing Mass under the Nail: Subungual Eccrine Poroma

Eccrine poroma is a benign adnexal tumour, which originates from the acrosyringium of eccrine sweat glands. Eccrine poroma is an uncommon neoplasm, the typical clinical presentation of which is a solitary soft sessile reddish papule protruding from a cup-shaped shallow depression. Many challenges remain in the diagnosis of eccrine poroma because it does not always present with classical features and may mimic any other cutaneous benign and malignant lesions. Eccrine poromas may occur on any skin surface with sweat glands; on the other hand, the most common sites of involvement include the palms and soles, which are rich in eccrine sweat glands. Here, we present a case of subungual eccrine poroma, which is an extremely rare presentation of poromas. We also highlight dermoscopic features of eccrine poroma and review the available literature on the subject.