Disseminated superficial actinic porokeratosis co-existing with linear and verrucous porokeratosis in an elderly woman: Update on the genetics and clinical expression of porokeratosis

Porokeratoses: an update on pathogenesis and treatment

Porokeratoses (PK) are a group of uncommon dermatoses characterized by abnormal epidermal differentiation due to a disorder of the mevalonate metabolic pathway. Several clinical subtypes exist that can be associated with the same patient or affect different patients within a family and could, therefore, be different expressions of one disease. All PK subtypes share a common histopathologic finding, the cornoid lamella, a vertical stack of parakeratotic corneocytes embedded in an orthokeratotic horny layer. PK often affects immunosuppressed patients, in whom the course may parallel the level of immunosuppression. The pathogenesis of PK, which had long remained mysterious, has been recently unraveled after discovering pathogenic variants of genes involved in the mevalonate metabolic pathway. The disease is due to germline pathogenic variants of genes of this pathway but requires a second-hit event to manifest; therefore, PK is considered a dominantly inherited but recessively expressed condition. The prognosis of PK is usually favorable, even though the lesions progress to keratinocyte carcinomas in 7%-16% of patients. The treatment of PK was based on physical (ablative) procedures and various (topical or systemic) treatments, whose efficacy is nevertheless inconsistent and often temporary. The discovery of the metabolic pathway involved in the pathogenesis of PK paved the way for the elaboration of new topical treatments (combination of statins and cholesterol), which are more regularly efficacious compared with older treatments, even though the management of some patients with PK may still be challenging.

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

Porokeratosis is a heterogeneous group of keratinising disorders characterised by the presence of particular microscopic structural changes, namely the presence of the cornoid lamella. This structure develops as a consequence of a defective isoprenoid pathway, critical for cholesterol synthesis. Commonly recognised variants include disseminated superficial actinic porokeratosis, disseminated superficial porokeratosis, porokeratosis of Mibelli, palmoplantar porokeratosis (including porokeratosis palmaris et plantaris disseminata and punctate porokeratosis), linear porokeratosis, verrucous porokeratosis (also known as genitogluteal porokeratosis), follicular porokeratosis and porokeratoma. Apart from the clinical presentation and epidemiology of each variant listed, this review aims at providing up-to-date information on the precise genetic background, introduces imaging methods facilitating the diagnosis (conventional and ultraviolet-induced fluorescence dermatoscopy, reflectance confocal microscopy and pathology), discusses their oncogenic potential and reviews the literature data on the efficacy of the treatment used, including the drugs directly targeting the isoprenoid-mevalonate pathway.

Case Report: A Novel MVK Missense Mutation in the Sporadic Porokeratosis Ptychotropica in China

Porokeratosis ptychotropica (PPt) is a rare type of porokeratosis (PK) characterized by pruritic, reddish-brownish verrucous papules, and plaques usually around genital area or buttocks. Here, a case of a 70-year-old woman who was diagnosed as PPt was reported. The patient suffered from severe pruritic papules and plaques in the buttock region and pubis for 4 years. The skin lesions were giant, well-defined brown plaques with many satellite papules scattered around. Both clinical manifestations and histopathological features supported the diagnosis of PPt. In review of the identified mutation was found in patients with disseminated superficial actinic porokeratosis (DSAP) combined with PPt, while its unclear in PPt. To investigate the hypothesis that the variant reported in the present case report may played as an independent "likely pathogenic factor" of PPt. Consequently, a de novo missense pathogenic mutation in the MVK gene was identified in this case. Unexpectedly, it is a first report of a novel MVK mutation in sporadic PPt. This rare case suggested an isogenetic background between PPt and DSAP, which may help to explore the underlying pathogenesis of PPt.

Disseminated Superficial Actinic Porokeratosis (DSAP): A Case Report Highlighting the Clinical, Dermatoscopic, and Pathology Features of the Condition

Porokeratosis describes a heterogenic group of keratinization disorders in which lesions are papules and plaques that demonstrate central atrophy surrounded by a hyperkeratotic margin. Clinical variants include not only porokeratosis of Mibelli, but also disseminated superficial, disseminated actinic superficial, linear, punctate, and palmaris et plantaris disseminata. Porokeratosis has a risk of malignant transformation. A woman with disseminated superficial actinic porokeratosis (DSAP) whose lesions presented as pruritic plaques and papules is described. The diagnosis was suspected clinically, supported by dermoscopy findings, and confirmed histologically. The condition-associated pruritus was managed symptomatically; her skin lesions will be monitored clinically. Clinical manifestations, dermatoscopic features, pathology findings, and treatment options for DSAP are summarized.

Mixed porokeratosis with a novel mevalonate kinase gene mutation: A case report

BACKGROUND

Porokeratosis is a rare, acquired, or inherited disorder of keratinization. There are numerous clinical types of porokeratosis and they can coexist in one patient and multiple members of an affected family. However, coexistence of disseminated superficial actinic porokeratosis (DSAP) and porokeratosis ptychotropica (Ppt) is rare.

CASE SUMMARY

A 45-year-old man presented with long-standing skin lesions. Physical examination identified numerous small, brown 2-mm 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 indicated a cornoid lamella in the epidermis. We identified c.155G>A mutation in the mevalonate kinase (MVK) gene, which converted a serine residue to asparagine (p.Ser52Asn) and was causative for porokeratosis in this family. A 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 more than 10 times using a microwave knife.

CONCLUSION

An unusual case of DSAP coexisting with Ppt harbored a novel MVK gene mutation also present in the patient’s family.

A Case Report of Porokeratosis Ptychotropica in a Chinese Man

Porokeratosis ptychotropica is a rare form of porokeratosis characterized by dyskeratotic skin lesions around genital area or gluteal cleft. Herein, a case of porokeratosis ptychotropica was reported. The patient was a 35-year-old man, who complained of pruritic papules and plaques in the perianal and buttock region for thirteen years. On examination, well-demarcated brown plaques with a verrucous white surface and multiple satellite papules were located along the gluteal folds and buttocks sparing the anus. Histopathological examination was consistent with porokeratosis. Combined with clinical manifestations and histopathologic changes, the patient was diagnosed as porokeratosis ptychotropica. He was treated with oral acitretin 30mg/d and CO₂ laser treatment, but the lesions showed no evident improvement after three months. Although it is not a new case, this condition is an extremely rare one that must be reviewed and emphasized. The dermatologist should keep porokeratosis ptychotropica in mind as one differential diagnosis for pruritic papules in the anogenital region.

[CME Dermatology 24: Porokeratosis]

CME Dermatology 24: Porokeratosis Abstract. Porokeratoses are a heterogeneous group of cornification disorders with the characteristic histological feature of the cornoid lamellae in the area of the marginal ridge. It is a rare but characteristic disease that occurs primarily in adulthood. Men are slightly more likely to be affected. The etiopathogenesis that leads to the transformation of the keratinocytes remains unclear; associations with genetic mutations and trigger factors such as UV rays and immunosuppression were observed. Due to the risk of malignant degeneration, consistent sun protection and regular clinical controls should take place. Cryotherapy, ablative laser therapy, curettage, photodynamic therapy or topical application of fluorouracil (5-FU), imiquimod and retinoids can be used to treat itchy, painful or cosmetically disturbing porokeratoses, depending on the location and severity.

Drugs associated with development of porokeratosis: A systematic review

Porokeratosis is a rare disorder characterized by atrophic macules or patches, with a well-defined ridge-like hyperkeratotic border called cornoid lamella. Although the exact pathogenesis is unknown, drug associated cases have recently been reported in the literature. As such, we systematically reviewed and identified drugs associated with drug-induced porokeratosis, their resultant effects, and whether there was a casual relationship between the use of a drug and the development of porokeratosis. We searched for articles which reported drug-induced porokeratosis in MEDLINE and Embase in June 2020. After full-text review, 25 studies were included for analysis. We identified 26 patients with drug-induced porokeratosis. The most common therapies associated with development of porokeratosis is biologic use, phototherapy, and radiotherapy. The most common clinical variants were the disseminated superficial or actinic types (60%), which occurred in psoriasis patients undergoing phototherapy, and eruptive disseminated type (24%) which occurred in the context of biologic therapies. The Naranjo score ranged from possible to probable for the identified treatments. Clinicians should consider drug reactions as possible triggering events for porokeratosis, especially for patients taking biologics, phototherapy, and radiotherapy. Large-scale studies are required to confirm our findings and further explore the pathogenesis for drug-induced porokeratosis.

Porokeratosis: A Review of Its Pathophysiology, Clinical Manifestations, Diagnosis, and Treatment

Porokeratosis comprises a group of heterogeneous and uncommon acquired or congenital skin diseases of unknown origin characterized by a keratinization disorder resulting from abnormal clonal expansion of keratinocytes. Numerous genetic mutations are thought to be involved. These conditions are characterized histologically by the presence of a cornoid lamella. Clinical manifestations are variable, with localized, disseminated, and even eruptive forms. Porokeratosis has been associated with immunosuppression, ultraviolet radiation, and systemic, infectious, and neoplastic diseases. Many authors consider it to be a premalignant condition because of the potential for malignant transformation to squamous cell or basal cell carcinoma. Therefore, long-term follow-up is a key component of treatment, which is usually complex and often unsatisfactory. We review the latest advances in our understanding of the pathogenesis, diagnosis, and treatment and propose a treatment algorithm.

Disseminated Superficial Actinic Porokeratosis in a Patient with Psoriasis, after Long-Term Narrowband Ultraviolet B Phototherapy

Porokeratosis is a rare epidermal disorder characterized by annular or linear hyperkeratotic plaques with slightly raised thread-like borders, and in most cases, atrophic centers. Disseminated superficial porokeratosis and disseminated superficial actinic porokeratosis (DSAP), which primarily involve sun-exposed areas, are common types of porokeratoses. Histologically, a column of parakeratotic cells, a so-called cornoid lamella, is a hallmark of porokeratosis. Porokeratosis is considered to result from the inability to eliminate an abnormal keratinocyte clone induced by genetic factors and various stimuli, including sunlight, artificial ultraviolet light, viral infections, immunosuppressive conditions (hematologic malignancies, organ transplants, or autoimmune disease), and immunosuppressive therapies. Here, we report a 59-year-old Korean woman with DSAP that developed after narrowband ultraviolet B (NB-UVB) therapy for psoriasis. Our case emphasizes the occurrence of DSAP due to NB-UVB that is able to induce local immunosuppression at the irradiated site; the pathogenesis of DSAP remains unclear.

Lesions of the mons pubis: a review

The mons pubis may become involved in dermatologic conditions or gynecologic lesions affecting the vulva. There are also unusual lesions that have been reported arising from the mons specifically. A familiarity with these lesions will be helpful if a patient with a lesion of the mons is encountered.

Disseminated superficial actinic porokeratosis on the face treated with imiquimod 5% cream

Porokeratoses are a group of hereditary or acquired disorders characterized by annular lesions with an atrophic center and a prominent peripheral ridge. Pathologically, porokeratosis is characterized by the presence of abnormal clones of keratinocytes that form a column of parakeratotic cells, called the cornoid lamella. Fifteen percent of patients of disseminated superficial actinic porokeratosis (DSAP) have facial lesions; other regions like the extensor surface of extremities constitute the majority of reported cases. Exclusively facial lesions are probably less frequent. Rarely, actinic porokeratosis is confined to the nose only. Of reported porokeratosis cases, 7.5% have revealed a malignancy arising within the lesion. We present a case of facial sporadic DSAP that was treated with imiquimod 5% cream in conjunction with a regular sunscreen. Follow-up of this case is important to rule out the possibility of malignant transformation of the lesions.

Progressive Disseminated Superficial Actinic Porokeratosis: a Case Report with a Family History in Three Generations

Disseminated superficial actinic porokeratosis is the most common form of porokeratosis in adults, which develops in the third or fourth decade of life, but may also occur later or earlier, more frequently in females, particularly in countries with high sun exposure. Lesions are numerous, uniform, superficial with central atrophy, demarcated by a distinct peripheral ridge, and usually found on sun exposed areas or elsewhere. The disease is inherited as an autosomal dominant condition. We present a 57-year-old retired woman. Her initial skin changes, affecting the face, developed in her thirties, and they have not changed their features since. In the following years, changes developed on the extensor surface of her arms and legs, with more prominent erythema, and then also on other parts of the body, including palms and soles, presenting as dark brown pigmented patches. Her mother had similar changes, and her daughter, who lives abroad, also has them. On examination, the patient presented with facial lesions, patches 2-3 mm wide, with peripheral hyperpigmentation and a pale center. There were multiple, 2-3 mm wide, dark brown lesions on the extremities and trunk. The lesions were either flat or with atrophic center with darker filiform corneal rim. Pathohistolgical examination revealed a "cornoid lamella", which is pathognomonic for the diagnosis of porokeratosis. Auxiliary diagnostic methods were also used - dermoscopy and Gentian violet staining. The patient was advised to avoid sun exposure and to apply photoprotective sunscreens. In conclusion, this is a case report of a disseminated superficial actinic porokeratosis that affected three generations of a family. Our patient developed lesions on palms and soles as well. A review of available world literature shows that this is the second case report of disseminated superficial actinic porokeratosis with palmoplantar involvement.

Linear porokeratosis: a case report

Porokeratosis is a rare genodermatosis based on chronic keratinization disorder histologically characterized by the presence of a cornoid lamella and various clinical manifestations. Five most commonly described types of poroketarosis are porokeratosis of Mibelli or ”classic” porokeratosis, disseminated superfi cial actinic porokeratosis, disseminated palmoplantar porokeratosis, linear porokeratosis, and punctate porokeratosis. In all of the fi ve clinical types of porokeratosis described today, cases of planocellular skin carcinoma are described, except in punctate type cases. Use of topical CO2 laser ablation, cryotherapy and topical use of 5% Imiquimod cream, have shown favorable effects in local treatment of porokeratosis. The authors present a clinical case of a girl suffering from linear porokeratosis over the course of the last four years, spreading on the inside of her right arm along the lines of Blaschko. Linear porokeratosis was histologically confi rmed by biopsy of skin lesions and dermoscopy. Dermoscopic fi ndings, used as an auxiliary method, also indicated linear porokeratosis. Successful liquid nitrogen cryotherapy prompted the authors to present a case in which the applied treatment proved to be successful, but also to emphasize the need for timely treatment in order to prevent malignant alterations of these changes.

Late-onset disseminated superficial actinic porokeratosis in an elderly woman

Introduction

Disseminated superficial actinic porokeratosis (DSAP) is the most common form of porokeratosis. A case of late-onset DSAP is reported with an uncommon presentation in an elderly patient.

Methods

An 80-year-old woman, with diabetes mellitus treated with metformin, and hypertension treated with metoprolol and captopril, presented with multiple 2 mm-to-7 cm brown patches, for 5 years. The patches were often confluent with an atrophic center and a well-demarcated keratotic border located on the thighs, lower legs, and feet.

Results

Histological examination of a cutaneous biopsy showed the presence of rare cornoid lamellae, confirming the clinical diagnosis of DSAP.

Conclusion

In this report, the atypical presentation of DSAP is discussed in this elderly patient and also the possible triggering factors at this age.

[Centrifugal plaques with central atrophy and peripheral scale on the scalp]

A 62-year-old man presented with slowly progredient, centrifugal, peripherally hyperkeratotic, centrally atrophic, slightly pruritic lesions on his scalp for at least 9 months. A punch biopsy stained with hematoxylin-eosin (HE) revealed minimal epidermal acanthosis and chimney-like parakeratosis (cornoid lamella) around a follicle. Discrete spongiosis of the epidermis was observed, as well as a lymphocytic cell infiltration in the papillary dermis. Based on the clinical picture and the histopathological examination the diagnosis of porokeratosis of Mibelli was made. Topical treatment was started using an urea and vitamin A acid preparation.