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

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.

Application of Ultraviolet-Enhanced Fluorescence Dermoscopy in Basal Cell Carcinoma

INTRODUCTION

Basal cell carcinoma (BCC) is the most common non-melanoma skin cancer. The aim of the current study was to analyze the ultraviolet-enhanced fluorescence dermoscopy (UVFD) characteristics of BCCs.

METHODS

BCCs were evaluated under polarized dermoscopy (PD) and UVFD. The findings in PD were described using predefined parameters for dermoscopic evaluation in dermato-oncology. UVFD characteristics were determined based on personal observations, and included interrupted follicle pattern, absence of pink-orange or blue-green fluorescence, well-demarcated borders, and dark silhouettes.

RESULTS

In total, 163 BCCs were analyzed. Under UVFD, the interrupted follicle pattern (p < 0.001), absence of pink-orange fluorescence (p = 0.005) and well-demarcated borders (p = 0.031) were more frequently noted in BCCs < 5 mm than in bigger tumors. Lesions on the face showed clearly defined borders (p = 0.031) and interrupted follicle pattern (p < 0.001) more frequently than tumors located beyond the face. Nodular BCCs displayed interrupted follicle pattern (p = 0.001) and absence of pink-orange fluorescence (p < 0.001) more commonly than superficial subtypes. Non-pigmented BCCs more frequently showed lack of blue-green fluorescence (p = 0.007) and interrupted follicle pattern (p = 0.018) compared to pigmented variants.

CONCLUSIONS

UVFD may be a valuable, complementary to PD, tool in the diagnosis of BCC, particularly in small tumors, lesions located on the face and nodular or non-pigmented subtypes.

Porokeratosis of Mibelli Treated With Topical 2% Lovastatin/2% Cholesterol Ointment

Porokeratosis is characterized by disruptions in the isoprenoid pathway, leading to the development of cornoid lamella, a unique skin lesion consisting of parakeratotic cells. The condition has a genetic foundation involving mutations affecting cholesterol synthesis, and new treatments aim to address these metabolic disruptions. This study examines a 56-year-old male with porokeratosis of Mibelli (PM) who presented with a non-healing erosion on his finger that persisted for two years. Previous therapies, including corticosteroids, antibiotics, and tacrolimus, proved ineffective. The patient then received a novel treatment with a topical 2% lovastatin/2% cholesterol ointment. After nine months, there was significant clinical improvement; the lesion was markedly reduced in size and appearance. This case underscores the potential of lovastatin/cholesterol ointment as an effective treatment for PM, indicating its promise for broader therapeutic applications.

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.

Applications of Ultraviolet and Sub-ultraviolet Dermatoscopy in Neoplastic and Non-neoplastic Dermatoses: A Systematic Review

Dermatoscopy is a non-invasive and cost-efficient imaging technique augmenting clinical examination in neoplastic and non-neoplastic dermatoses. Recently, novel dermatoscopic techniques based on principles of reflectance/absorption and excited fluorescence have been developed. However, comprehensive data on their applications are sparse, and terminology is inconsistent. In this systematic review, we addressed the principles of ultraviolet (UV) imaging and proposed categorization based on spectral characteristics and signal acquisition, as well as discussed documented and potential clinical applications, safety measures during examination, and limitations associated with reflectance and fluorescence dermatoscopy. A literature search was conducted in the PubMed medical database until 2 December 2023 according to PRISMA guidelines, and 28 papers fit the scope of this review, whereas additional relevant articles were included to provide broader context regarding the chosen terminology, chromophores described, safety of sub-UV/UV, and regulations for light-emitting devices. UV and sub-UV dermatoscopy, categorized into different methods on the basis of the emitted wavelength and signal acquisition process (reflectance versus fluorescence), augment conventional dermatoscopy by optimizing safety margins in melanoma, facilitating early detection of tumor recurrence, and enhancing visualization in non-neoplastic conditions, including pigmentation disorders, intertrigo, papulo-desquamative dermatoses, and beyond. The review highlights the limitations of these techniques, including difficulty in differentiating melanin from hemoglobin, challenges in evaluating uneven surfaces, and artifacts. Although UV dermatoscopy complements conventional dermatoscopy, clinicians should be aware of their peculiarities, artifacts, limitations, and safety concerns to optimize their diagnostic accuracy and ensure patient's safety.

Disseminated Superficial Porokeratosis: A Case Report

Disseminated superficial porokeratosis is a rare dermatological disorder characterized by annular keratotic lesions, presenting diagnostic challenges due to its variable clinical manifestations. The pathogenesis involves genetic predisposition and environmental factors, with mutations in the mevalonate pathway implicated. Despite its benign nature, this condition significantly impacts patients' quality of life, necessitating accurate diagnosis and effective therapeutic strategies. We present the case of a 45-year-old female with a three-year history of annular plaques on sun-exposed areas progressing to involve multiple body regions. The characteristic histopathological finding of coronoid lamellae confirmed the diagnosis of disseminated superficial porokeratosis. Treatment involved a multimodal approach, including topical corticosteroids, calcineurin inhibitors, and systemic retinoids, resulting in satisfactory clinical outcomes. Long-term follow-up emphasized the need for ongoing disease monitoring and patient education regarding sun protection. The presented case underscores the importance of recognizing characteristic histopathological features for accurate diagnosis and highlights the significance of long-term follow-up, disease monitoring, and patient education to optimize outcomes and enhance overall quality of life.