Abstract

Porokeratosis is a clonal disorder of keratinization with characteristic histologic findings on biopsy. Porokeratosis isolated to the genitals, without disseminated disease, is regarded as an extremely uncommon presentation. An otherwise healthy 40-year-old male presented with a 2 year history of a solitary, annular plaque on his scrotum, initially diagnosed as tinea. He was unsuccessfully treated with topical antifungals, topical steroids, and topical tacrolimus. A biopsy was performed which revealed columns of parakeratosis at 45 degree angles, consistent with cornoid lamella, a distinct finding of porokeratosis. A review of the literature revealed 59 total cases, including the current case, of porokeratosis confined strictly to the genital region. The review confirmed that genital porokeratosis has a strong predilection for males (93%; 55/59 cases) with an average age of 41 years (range 8-75 years). In male patients, the scrotum was the most frequently involved body part (65%; 36/55 cases). It often presents with an annular plaque and raised borders (50%; 23/46 of cases with a description). Most lesions were present for at least a year with multiple failed topical treatments before a biopsy was performed. Of the few cases that listed a differential diagnosis, genital porokeratosis appeared only twice. The current case and subsequent literature review demonstrate that genital porokeratosis continues to be exceptionally difficult to diagnose at the onset of clinical presentation. Prompt recognition of the clinical and pathologic features of this rare entity can lead to improved patient care and management.

Financial Disclosure:
No current or relevant financial relationships exist.