Linear porokeratosis of mibelli: successful treatment with cryotherapy

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.

Topical Administration of a Novel Acetylated Tetrapeptide Suppresses Vascular Permeability and Immune Responses and Alleviates Atopic Dermatitis in a Murine Model

Although the pathogenesis of atopic dermatitis (AD) remains to be fully deciphered, skin barrier abnormality and immune dysregulation are known to be involved. Recently, the vascular endothelial growth factor (VEGF)/VEGF receptor (VEGFR) system has also been implicated in the pathogenesis of this multifactorial chronic inflammatory skin disorder. Previously, we showed that a novel tetrapeptide, N-acetyl-Arg-Leu-Tyr-Glu (Ac-RLYE), inhibits angiogenesis and vascular permeability effectively by selectively antagonizing VEGFR-2. The current study aimed to investigate the pharmacological effect of Ac-RLYE on AD in vitro and in vivo. The in vitro experiments demonstrated that Ac-RLYE inhibited VEGF-induced vascular permeability in endothelial cells. Moreover, in an in vivo animal model of AD, Ac-RLYE relieved AD-like symptoms such as ear thickness and dermatitis severity scores and infiltration of immune cells, including mast cells and eosinophils. Ac-RLYE inhibited IgE secretion, restored the skin barrier protein filaggrin level, and markedly downregulated gene expression of AD-related Th1, Th2, and Th17 cytokines. Collectively, these findings suggest that Ac-RLYE would be useful for the treatment of AD and associated inflammatory skin disorders.

[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.

Treatment of Porokeratosis: A Systematic Review

BACKGROUND

Porokeratosis (PK) is a rare skin disease of unknown etiology. It consists of a keratinization disorder, which may appear in several clinical forms and can undergo malignant transformation. The histopathological hallmark of PK is the cornoid lamella. While many topical, systemic, and surgical treatment modalities for PK have been described, no randomized controlled trials have been performed yet. Because of a lack of treatment standards for PK, European and international guidelines cannot be created.

OBJECTIVE

The aim of this systematic review is to outline options for treating PK.

METHODS

We performed a systematic literature search in an electronic database for published literature. A total of 88 articles fulfilling our inclusion criteria were found.

RESULTS

There were no randomized controlled trials on the treatment of PK, but mainly case reports and case series. Porokeratosis of Mibelli showed the best outcomes after treatment with imiquimod cream and linear PK responded well to topical or systemic retinoids. Topical vitamin D acid derivatives may be the best therapeutic option for disseminated PK. Surgical interventions and cryotherapy may be preferred in areas where the use of topical agents is difficult or contraindicated.

CONCLUSION

To offer patients with PK an evidence-based high-quality standardized therapy, randomized controlled trials are needed.

Facial follicular porokeratosis: a case report

Porokeratosis is a disorder of keratinization, characterized clinically by a peripheral keratotic ridge and histologically by the cornoid lamella. We describe a patient with follicular porokeratosis with a distinctive clinical presentation. We believe that follicular porokeratosis is a unique histopathologic variant of porokeratosis, with cornoid lamellae centered in follicular infundibula. Further, this is the only report of follicular porokeratosis involving the face exclusively.

A case study of Mibellis disease with unilateral lesion foci

A case study of the classical form of a rare form of inherited dermatosis, Mibellis disease, featuring unilateral position of the foci in a child aged 3. A histological examination revealed aggregations of parakeratotic cells in epidermis being characteristic of Mibellis disease.

Possible pathogenic role of Th17 cells for atopic dermatitis

The critical role of IL-17 has recently been reported in a variety of conditions. Since IL-17 deeply participates in the pathogenesis of psoriasis and keratinocyte production of certain cytokines, the involvement of T helper cell 17 (Th17) in atopic dermatitis (AD) is an issue to be elucidated. To evaluate the participation of Th17 cells in AD, we successfully detected circulating lymphocytes intracellularly positive for IL-17 by flow cytometry, and the IL-17+ cell population was found exclusively in CD3+CD4+ T cells. The percentage of Th17 cells was increased in peripheral blood of AD patients and associated with severity of AD. There was a significant correlation between the percentages of IL-17+ and IFN-gamma+ cells, although percentage of Th17 cells was not closely related to Th1/Th2 balance. Immunohistochemically, IL-17+ cells infiltrated in the papillary dermis of atopic eczema more markedly in the acute than chronic lesions. Finally, IL-17 stimulated keratinocytes to produce GM-CSF, TNF-alpha, IL-8, CXCL10, and VEGF. A marked synergistic effect between IL-17 and IL-22 was observed on IL-8 production. The number of Th17 cells is increased in the peripheral blood and acute lesional skin of AD. Th17 cells may exaggerate atopic eczema.

Successful treatment of disseminated superficial actinic porokeratosis with Q-switched ruby laser

Porokeratosis, a cutaneous disorder that is characterized histologically by the presence of a "cornoid lamella", is a progressive disease with limited therapeutic modalities. We report a case of a 61-year-old man suffering from disseminated superficial actinic porokeratosis, one of the clinical types of porokeratosis, treated with Q-switched ruby laser, commonly used for the treatment of pigmented skin diseases. The laser therapy provided striking improvement and no clinical recurrence was noted.

Generalized linear porokeratosis

A 23-year-old woman was seen for widespread skin lesions present since the age of 2.5 years. Twenty years ago, she developed a brown macular lesion on her right buttock. The lesion became hyperkeratotic and subsequently spread through the posterior aspect of her right leg. It later spread to the right side of the trunk and to the right arm. When she was 9 years old, she developed similar lesions on her left arm and leg. After she was 13 years old, no new skin lesions appeared. There was no family history of similar lesions. On examination, there were numerous linear and whorled, reddish-brown, hyperkeratotic plaques, with central atrophy and raised borders, following Blaschko's lines on all of the extremities. These lesions on the extremities extended to the dorsum of the hands and feet (Fig. 1). She had hyperkeratotic lesions on the pressure points of both of the soles, but no palm involvement. The number of lesions on the right side was greater than that on the left. Reddish-brown annular plaques with central atrophy and raised borders, appearing in zosteriform configuration, and numerous individual 2-3-mm erythematous lichenoid papules were observed on the right side of the thorax and the right inguinal region (Fig. 2). No face, scalp, or mucous membrane involvement was seen. The nails of the second and fifth fingers of the right hand and the nail of the third finger of the left hand showed nail dystrophy with longitudinal ridges and pterygium. All the nails of the right foot and the nails of the first and fifth toes of the left foot showed dystrophic changes with subungual keratosis. The patient was otherwise in good health. Two biopsy specimens taken from a hyperkeratotic plaque and a lichenoid papule showed an epidermal invagination with angulated parakeratotic tier, denoting cornoid lamella. The epidermis just underneath the cornoid lamella displayed vacuolization and the granular layer was absent. The adjacent epidermis was atrophic, and hydropic degeneration within the basal cell layer was seen. In the dermis, a nonspecific, mild, chronic, inflammatory cell infiltrate, telangiectatic vessels, and pigment-laden macrophages were present. These findings were consistent with linear porokeratosis (Fig. 3). Microscopic examinations and mycologic cultures of the nails were negative. We decided to treat our case systemically with retinoids, but the patient refused this therapy. So, topical tretinoin 0.05% was started once a day. A marked improvement was observed in hyperkeratosis through the first 4 weeks of treatment and plateaued at 8 weeks. After 10 weeks, the lesions had almost disappeared. We planned to continue the applications every other day. One year later, she remains stable with application of topical tretinoin 0.05% twice a week and is satisfied with the final appearance. She is under regular follow-up.

Linear porokeratosis associated with disseminated superficial actinic porokeratosis: a new example of type II segmental involvement

The coexistence of linear porokeratosis (LP) and disseminated superficial actinic porokeratosis (DSAP) in a 3-year-old girl with a family history of DSAP is presented. Happle proposed loss of heterozygosity (LOH) to explain the origin of this unusual phenomenon. Homozygosity would explain why lesions in LP are far more pronounced than those of the associated heterozygous DSAP lesions. LOH would also explain the early age of presentation of the linear lesions, the family history of DSAP, and why LP cases are particularly prone to malignant transformation. This case is also important for molecular studies because of the presence of heterozygous and homozygous mutated cells in the same patient and the familial occurrence of the heterozygous form of the disease.