[Verrucous variant of porokeratosis of Mibelli as a differential diagnosis of psoriasis vulgaris]. / Verruköse Variante der Porokeratosis Mibelli als Differenzialdiagnose der Psoriasis vulgaris.

In a 37-year-old man, diagnosis of verrucous porokeratosis could only be made by histological examination. Previously, the skin lesions on the right buttock had been treated by several dermatologists as psoriasis vulgaris. The clinical picture of both dermatoses was characterized by sharply defined, erythematous papules and plaques. Precise evaluation of the clinical morphology was key for diagnosis. Moreover, in contrast to psoriasis, verrucous porokeratosis is characterized by a high degree of treatment resistance.

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.

Challenges in the Diagnosis and Management of Giant Porokeratosis: A Case Report.

Porokeratosis encompasses a diverse group of dermatoses, both acquired and genetic, marked by a keratinization disorder. Porokeratosis of Mibelli (PKM) presents as solitary plaques or multiple papules/macules with central atrophy and raised hyperkeratotic borders. Here, we present a case of giant porokeratosis (GPK), a rare form often considered a morphological variant of PKM, with unique clinical and histopathological aspects. Our case involves a 29-year-old patient with a 15 × 10 cm irregular plaque on the dorsal aspect of the right hand. The patient was previously prescribed various topical treatments (retinoids, calcineurin inhibitors, and combinations of corticosteroids with vitamin D3 analogs) and systemic retinoids without improvement before presenting to our department. Due to the high risk of neoplastic transformation and the unavailability of imiquimod, the patient was recommended topical 5-fluorouracil treatment. The trajectory of the lesion under treatment revealed a favorable evolution, and the patient was subjected to regular monitoring every three months to assess the ongoing progress. Recognizing GPK as a high-risk variant is crucial for dermatologists, and it requires a personalized approach. Regular monitoring is advised to detect potential malignant transformations promptly. Future research holds promise for diagnostic advancements, refined treatment modalities, and a deeper understanding of the molecular mechanisms underlying malignancy in porokeratosis.

Presentations of Cutaneous Disease in Various Skin Pigmentations: Porokeratosis.

Description Porokeratosis was first described in 1893. It is a relatively rare disorder with over 9 subtypes. Lesions are clinically characterized as well-demarcated, erythematous papules (raised, <1 cm) or plaques (raised, >1 cm), with an atrophic center, and raised scaly border. Porokeratosis is an important diagnosis to identify because it may undergo malignant transformation and mimics many commonly encountered diagnoses. These commonly mimicked diagnoses include squamous cell carcinoma, tinea corporis, nummular dermatitis, and psoriasis vulgaris, to name a few. The clinical images in this review focus on identifying porokeratosis along the full spectrum of skin tones.

Porokeratosis ptychotropica: a rare and evolving variant of porokeratosis.

Porokeratosis ptychotropica represents a rare and under-recognized variant of porokeratosis. There are also alternative descriptions for this disorder in the literature. Since its original description in 1995, additional characteristic features have been showed in case reports published in the literature. These cumulative reports, although still limited in numbers, have helped to further shape and define this entity. A case report and review of published literature on this unusual entity are presented. The specific combination of clinical, morphological and histopathological characteristics that can facilitate recognition of the disorder is discussed. There has been a call for uniformity in terminology and a suggestion for alternative terminology has been made. However, we discuss why the earlier term, porokeratosis ptychotropica, is still preferred.

Exclusive and Solitary Facial Porokeratosis: Pathogenesis and Literature Reappraisal of a Rare Entity.

Porokeratosis is a group of well-known clinically distinct entities, characterised by different clinical aspects, but sharing a single common histological aspect, namely the cornoid lamella. Usually, porokeratosis occurs in the limbs and trunk, while it rarely involves the face, especially as an exclusive, single, and solitary lesion. We report the case of a 52-year-old Caucasian woman, with an 11-month history of a 2-cm slowly growing solitary, keratotic lesion on her left cheekbone. The patient did not present other cutaneous lesions on the face, as well as in other body sites. A cutaneous biopsy showed epidermal hyperplasia with multiple, sharply defined cornoid lamella, associated with an underlying attenuation of the granular layer and scattered dyskeratotic cells in the spinous layer. The superficial dermis underneath showed a mild lymphocytic infiltrate and fibrosis with remodelled collagen bundles. A final diagnosis of solitary facial porokeratosis was made.

A rare case of disseminated superficial porokeratosis-Case report.

Porokeratosis is a keratinization disorder characterized by hyperkeratotic sharply demarcated plaques with central atrophy and histopathologically, by cornoid lamella. A 30-year-old male presented with multiple pruritic dark raised skin lesions over the trunk, face, and upper limbs for past 3 years. Cutaneous examination revealed hyperkeratotic annular plaques with raised margins over face, trunk, and arms. Histopathology revealed marked hyperkeratosis with irregular acanthosis and papillomatosis. Vertical parakeratotic foci and focal hypergranulosis were seen. Hence, a diagnosis of disseminated superficial porokeratosis was made. We present this rare case which may have association with systemic disease, immunosuppression, and malignant transformation.

Porokeratosis: An enigma beginning to unravel.

Porokeratosis is a keratinization disorder with unclear etiopathogenesis, varied clinical presentation and characteristic histopathology, and is usually unresponsive to current therapeutic options. Until now, it was considered to be a clonal disorder with immunity, ultra violet radiation and other factors playing important roles in etiopathogenesis. It is now known that abnormalities in the mevalonate pathway are responsible for this clonal keratinization abnormality. New variants of porokeratosis like eruptive bullous, pruriginous, lichen planus like, follicular variants and porokeratoma have been described. While the cornoid lamella is the classical histopathologic feature, dermoscopy and reflectance confocal microscopy make the diagnosis clearer. Development of malignancy in a few variants is a concern. Linear, disseminated superficial actinic and giant lesions are most prone to developing malignancies. Bowen's disease, squamous cell carcinoma, basal cell carcinoma and even melanoma have been reported in cases of long-standing porokeratosis. Newer modalities of therapy such as photodynamic therapy, ingenol mebutate and HMGCoA inhibitors may play a role in the future.

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.

Porokeratosis Ptychotropica: Dermoscopy, Reflectance Confocal Microscopy, and Histopathological Correlation.

Porokeratosis ptychotropica (PP) is a rare variant of porokeratosis characterized by pruritic, symmetrical, red-brown verrucous papules, and plaques most commonly localized within the gluteal fold. Herein, we report the clinical, dermoscopy, and reflectance confocal microscopy (RCM) aspects of a case of PP in a 63-year-old Caucasian woman along with histopathological correlation. Both dermoscopy and RCM were able to recognize the cornoid lamella, the histopathological clue shared by all clinical variants of porokeratosis. These non-invasive techniques may help in the differential diagnosis with other inflammatory/infectious and neoplastic disorders that may clinically resemble PP, but show distinct patterns.

Generalized type 2 segmental disseminated superficial actinic porokeratosis coexisted with multiple cutaneous squamous cell carcinomas: Analysis of two cases.

Porokeratosis (PK) is defined as hyperpigmented macules or patches with a distinctive, ridge-like hyperkeratotic border which is histologically characterized by a cornoid lamella. Here, we report two cases of linear porokeratosis which converted to multiple cutaneous squamous cell carcinoma after long history progression. In addition, patient 2 was accompanied by secondary dermal amyloid deposits, which was rare reported.

Case Report on Rare Clinical Variant of Porokeratosis: Disseminated Superficial Porokeratosis.

Porokeratosis is a genodermatosis, resulting from a disorder in keratinization due to an abnormal clone of epidermal precursor, presenting with various clinical manifestations but characterized histologically by the presence of cornoid lamella. Diverse clinical variants of porokeratosis exist, which are unified by this general histological feature, but differ in morphology, distribution, and clinical course. The typical lesions of porokeratosis are described by an atrophic center surrounded by an elevated keratotic rim formed by the cornoid lamella. The lesions can be found almost anywhere on the body. We report an unusual presentation of a rare clinical variant, disseminated superficial porokeratosis.

Enhanced dendritic cells and regulatory T cells in the dermis of porokeratosis.

Porokeratosis is characterized clinically by annular lesions and histologically by the presence of a cornoid lamella (CL) in the epidermis. The underlying mechanism of porokeratosis development remains unclear. We performed immunohistochemical staining of CD1a, langerin, Ki67, CD3, CD4, CD8, FOXP3, and RANKL (receptor activator of nuclear factor κB ligand) in samples from 17 porokeratosis lesions and analyzed the differences in staining patterns among the CL, the inner part of the annular ridge (IC), and the adjacent normal skin (ANS). Numbers of CD1a+ Langerhans cells in the epidermis were reduced and numbers of CD1a+ dermal dendritic cells were significantly increased in the CL and IC compared to those in the ANS. In addition, there was also an increase in FOXP3+ cells in the dermis below the CL and IC. Our findings suggest that Langerhans cells are downregulated in the epidermis in CL and that regulatory T cells and dendritic cells are upregulated in the dermis below the CL. This alteration in the distribution of immune cells, such as various lymphocyte subsets, Langerhans cells, and dermal dendritic cells, may play a key role in the pathomechanisms of porokeratosis.

Punctate Porokeratosis Palmaris et Plantaris.

Porokeratosis, a keratinization disorder, is probably a group of unrelated conditions with same distinctive histological appearance, featuring cornoid lamellae. A case of punctate porkeratosis in a 24 year old male patient is reported for its rarity.