Penile porokeratosis mimicking annular lichen planus

Sir, Porokeratosis is a group of cutaneous diseases presented by epidermal keratinization [1]. Herein, we report the case of a patient with porokeratosis who responded well to carbon dioxide (CO2) laser therapy. A 22-year-old Vietnamese male visited our department with an asymptomatic plaque on the penis present for three months. He denied a family history of similar lesions. A cutaneous examination of the penis revealed an annular, well-circumscribed plaque with slightly raised borders with scales (Fig. 1a). Other mucocutaneous lesions were absent. Fungal microscopy, a rapid plasma reagin (RPR) test, and a Treponema pallidum hemagglutination (TPHA) test were negative. Histological findings revealed a hyperkeratotic lesion with a discrete parakeratotic column. There was the presence of a cornoid lamella, which was a parakeratotic column overlying a small vertical zone of dyskeratotic and vacuolated cells within the epidermis (Fig. 2a). There was also a focal loss of the granular layer. A mild lymphocytic infiltrate could be seen around an increased number of capillaries in the underlying dermis (Fig. 2b). CO2 laser removal was performed. There was no recurrence after a twelve-month follow-up (Fig. 1b). However, a hypopigmented scar was seen. Porokeratosis is an uncommon disorder of keratinization with clinical variants, such as classical porokeratosis of Mibelli, disseminated superficial actinic porokeratosis, linear porokeratosis, and porokeratosis palmaris et plantaris disseminata [2]. Porokeratosis involving the genital areas and other adjacent sites is rare [2]. Genital porokeratosis was first described by Helfman in 1985 [3]. More than 69 cases have been reported in the literature [1]. The pathophysiology of genital porokeratosis remains unknown. It has been supposed that porokeratosis is linked to repeated minor frictional trauma. A benign lesion may transform into squamous cell carcinoma or basal cell carcinoma [4]. However, no malignant transformation of genital porokeratosis has been noted in the literature. Genital porokeratosis manifests itself clinically as classic or plaque-type porokeratosis of Mibelli [2]. Histological findings revealed a cornoid lamella with the absence of a granular layer and dyskeratotic cells in the upper spinous zone [2]. Our case may mimic some annular lesions, such as secondary syphilis, fungal infection, and annular lichen planus. Because a fungal examination and syphilis serology were negative, we could exclude fungal infection and annular secondary syphilis. The distinctive histology of porokeratosis such as a cornoid lamella with a decreased granular layer may help to differentiate between porokeratosis and annular lichen planus [4]. Numerous therapeutic methods of treatment exist, including surgical excision, CO2 laser, cryotherapy, topical retinoids, 5% 5-fluorouracil, vitamin D3 analogs, imiquimod cream, and 3% diclofenac gel [2,5].

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.

Mevalonate Kinase-Associated Diseases: Hunting for Phenotype–Genotype Correlation

Mevalonate kinase-associated diseases (MKAD) are caused by pathogenic mutations in the mevalonate kinase gene (MVK) and encompass several phenotypically different rare and hereditary autoinflammatory conditions. The most serious is a recessive systemic metabolic disease called mevalonic aciduria, and the most recently recognized is disseminated superficial actinic porokeratosis, a dominant disease limited to the skin. To evaluate a possible correlation between genotypes and (1) the different MKAD clinical subtypes or (2) the occurrence of severe manifestations, data were reviewed for all patients with MVK variants described in the literature (N = 346), as well as those referred to our center (N = 51). The genotypes including p.(Val377Ile) (homozygous or compound heterozygous) were more frequent in mild systemic forms but were also sometimes encountered with severe disease. We confirmed that amyloidosis was more prevalent in patients compound heterozygous for p.(Ile268Thr) and p.(Val377Ile) than in others and revealed new associations. Patients homozygous for p.(Leu264Phe), p.(Ala334Thr) or compound heterozygous for p.(His20Pro) and p.(Ala334Thr) had increased risk of severe neurological or ocular symptoms. All patients homozygous for p.(Leu264Phe) had a cataract. The variants associated with porokeratosis were relatively specific and more frequently caused a frameshift than in patients with other clinical forms (26% vs. 6%). We provide practical recommendations focusing on phenotype–genotype correlation in MKAD that could be helpful for prophylactic management.