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.