An unusual case report of porokeratosis ptychotropica on the buttocks

Abstract

Rationale: Porokeratosis ptychotropica represents an unusual form of porokeratosis characterized by symmetrical dyskeratotic skin lesions on the gluteal clefts. Herein, we report a case of porokeratosis ptychotropica. Patient concerns: A 33-year-old man, who complained of itching papules and plaques in the gluteal cleft and the buttocks for the last 7 years. Clinical examination showed a large well-defined reddish brown verrucous plaque located on both buttocks along with satellite papules on the inner thigh. Dermoscopy and histopathological findings were consistent with porokeratosis. Diagnosis: He was diagnosed with porokeratosis ptychotropica. Outcomes: No significant improvement was observed following treatment with oral acitretin and a topical retinoid. Lessons: The case report highlights the need for awareness amongst dermatologists for porokeratosis ptychotropica as a differential diagnosis for pruritic papules in the gluteal fold.

Porokeratoses—A Comprehensive Review on the Genetics and Metabolomics, Imaging Methods and Management of Common Clinical Variants

“…VP may mimic many dermatological conditions (esp. inverse psoriasis, but also viral warts, perianal Paget's disease, Darier's disease, Hailey-Hailey disease, epidermal nevus, seborrheic keratosis, lichen planus verrucosus, lichen simplex chronicus, contact dermatitis, neurodermatitis, Zoon's balanitis, dermatophytosis, chromomycosis, paracoccidioidomycosis, squamous cell carcinoma, sebaceous carcinoma, condyloma acuminata, granuloma annulare, lichen sclerosus, morphea, verrucous cutaneous tuberculosis, leishmaniasis, acrodermatitis enteropathica and necrolytic migratory erythema), the patients usually report multiple treatment failures and are subjected to delayed diagnosis [464,465,467,469,474,477,485,487,[491][492][493][494][495]. Thus, the disease is suspected to be largely underdiagnosed and some cases may be treated as sexually transmitted infections [295,465,467].…”

“…A central scar-like or hyperpigmented area, polarising-specific white four-dotted clods (rosettes), clues of scale (thick curved parallel lines/cerebriform or papillomatous-like pattern, white or brown diffuse scales, follicular plugs) and a vascular pattern consisting of non-uniformly arranged dots or clods can be noted. Pigmented dots and clods on a reddish-brown background may occasionally occur [59,466,473,486,493,[501][502][503][504][505].…”