Acrokeratosis verruciformis of Hopf: Genetic, clinicopathologic and therapeutic features (Review)

Acrokeratosis verruciformis of Hopf (AVH) is a rare genodermatosis belonging to the group of epidermal differentiation diseases. It is due to the heterozygous missense mutation p.(Pro602Leu) in the ATPase sarcoplasmic/endoplasmic reticulum Ca²⁺ transporting 2 (ATP2A2) gene, which is also involved in Darier disease (DD), and is therefore considered an allelic form of DD. AVH is usually transmitted as an autosomal dominant trait with variable penetrance, although several sporadic cases have been reported. The disease manifests clinically with flat, wart-like papules with a verrucous surface that develop predominantly on the dorsum of the hands and feet, and appear early in life or, in sporadic cases, in adulthood. The lesions exhibit characteristic microscopic changes (verrucous epidermal hyperplasia with a 'church-spire-like' surface), which allow differentiation from DD. The course of the disease is chronic and the outcome as a rule benign, although rare cases of malignant transformation have been reported. Treatment is not necessary; it can be attempted at the request of the patient, knowing that no standardized treatment exists. Treatments that have been tested include topical agents (namely keratolytics, retinoids and cryotherapy) and systemic retinoids; however, the results are often modest. The present brief narrative review aimed to summarize the etiopathogenic, clinical, histopathological and therapeutic features of AVH.