Coexist of Disseminated Superficial Actinic Porokeratosis and Porokeratosis Ptychotropica with A Novel MVK Gene Mutation: A Case Report and Literature Review

Background: Porokeratosis is a rare, acquired or inherited disorder of keratinization. There are numerous clinical types of porokeratosis and they could coexist in one patient and in multiple members of an affected family. However, coexist of disseminated superficial actinic porokeratosis (DSAP) and porokeratosis ptychotropica (Ppt) is rare.Case presentation: A 45-year-old man presented with long-standing skin lesions. Physical examinations found numerous small, brown 2- to 4-mm patches on his face and several hyperkeratotic, verrucous plaques on his trunk and extremities. His father and one of his brothers also had similar lesions for years. Skin biopsies showed a cornoid lamella in the epidermis. And we identified c.155 G>A mutation of the mevalonate kinase (MVK) gene convertting a serine residue to asparagine (p.Ser52Asn) was the causative mutation for porokeratosis in this family. The clinicopathologic diagnosis of DSAP and Ppt with a novel MVK gene mutation was made. The hyperkeratotic plaques on the patient's scrotum were completely removed by microwave knife for more than 10 times. Conclusion: We report an unusual case of DSAP coexisting with Ppt and identified a novel MVK gene mutation in this patient's family. The microwave knife is an effective and safe therapy for porokeratosis.

Bilateral Porokeratosis Ptychotropica on the Gluteal Cleft: A Case Report and Review of the Literature

Porokeratosis ptychotropica (PP) is a rare variant of porokoretosis that is distinctive based on its clinical presentation of pruritic, verrucous papules and plaques that often form a “butterfly” shape, commonly located on the perinatal cleft with extension to the buttocks. Similar to other variants of porokeratosis, it is histologically distinguished by the presence of cornoid lamellae. Proper diagnosis is necessary as some studies suggest that PP may predispose to squamous cell carcinoma. Furthermore, there are limited evidence-based treatment options.We report the case of a47 year-old-male who presented with a rash on the buttocks and legs for 3 years. Physical exam revealed erythematous, annular, and verrucous plaques on the bilateral periglueteal area and bilateral distal lower extremities. The patient felt that lesions on the legs were disfiguring but otherwise asymptomatic. Biopsy results demonstrated hyperkeratosis and parakeratosis suggestive of cornoid lamellae. Clinical and histologic findings were suggestive of PP. Lesions on the legs were treated with cryotherapy, which resulted in resolution at a 3-month follow-up.PP remains a diagnostic and therapeutic challenge due to its rarity. No standard of care has been established, though topical calcipotriol, topical imiquimod, topical tretonoin, and cryotherapy have been used with success in the literature. This case highlights unique characteristics of PP in order to aid in early detection and cancer prevention while also describing various treatment modalities.