Track

Case Reports

Abstract

Background: White sponge nevus, a hereditary disorder of keratin, is classically described as a white spongy painless plaque on oral mucosal surfaces, with rare cases of painful plaques involving the vulva and rectum.

Objective: To describe a rare case of perianal white sponge nevus-like proliferation, recalcitrant to treatment.

Case: A 73-year-old male with a history of many perirectal surgeries for fissures since childhood presented with a several-year history of painful, pruritic perianal ulcerative plaques. He previously failed multiple topical medications (clobetasol, pimecrolimus, tacrolimus, topical retinoids) and numerous over-the-counter emollients. On exam of the perianal region, white hyperkeratotic mucosa with multiple well-demarcated, shallow ulcers of varying sizes, with overlying fibrinous tissue and surrounded by erythema extending to the buttock were present. Biopsies showed hyperkeratosis, mild epithelial hyperplasia, rounded parakeratosis, spongiosis, and mild epithelial atypia. Keratins 4 and 13 genetic testing of the buccal mucosa and perianal skin were negative. Based on the histology, this is a white sponge nevus-like proliferation. Treatment with 100 mg doxycycline BID achieved significant relief, but the patient subsequently flared when tapered.

Discussion: Extraoral manifestations of white sponge nevus have been described on female genitalia and the rectum. However, no treatment regimens for extraoral manifestations have been described; a previous review of oral white sponge nevus found high-dose doxycycline or amoxicillin efficacious. While low-dose doxycycline has anti-inflammatory properties, our patient’s disease was not stable with low-dose therapy. Differential diagnoses included ptychotropic porokeratosis, a disordered keratinization with a genitogluteal variety.