Cornoid Lamella-Like Structures in HIV-Associated Epidermodysplasia Verruciformis: A Unique Histopathologic Finding

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.

Acquired epidermodysplasia verruciformis: clinical presentation and treatment update

Acquired epidermodysplasia verruciformis (AEV) is a form of epidermodysplasia verruciformis (EV) that is most commonly found in immunocompromised or immunosuppressed patients. EV is commonly associated with human papillomavirus (HPV), which is often found in EV and AEV lesions. Clinical presentation of AEV in patients with organ transplantation, HIV+, congenital HIV+, hematological diseases, and other iatrogenic immunosuppression are reviewed. Treatment options include topical cidofovir, topical retinoids, topical imiquimod, topical glycolic acid, HPV 9-valent vaccine, acitretin, improving cellular immunity, and changing transplant medication to mycophenolate mofetil.

The Biology and Clinical Features of Cutaneous Polyomaviruses

Human polyomaviruses are double-stand DNA viruses with a conserved genomic structure, yet they present with diverse tissue tropisms and disease presentations. Merkel cell polyomavirus, trichodysplasia spinulosa polyomavirus, human polyomavirus 6 and 7, and Malawi polyomavirus are shed from the skin, and Merkel cell polyomavirus, trichodysplasia spinulosa polyomavirus, human polyomavirus 6 and 7 have been linked to specific skin diseases. We present an update on the genomic and clinical features of these cutaneous polyomaviruses.

Human polyomavirus-7-associated eruption successfully treated with acitretin

Advances in molecular technologies have led to the discovery of several novel human polyomaviruses (HPyVs), including human polyomavirus-7 (HPyV-7). Although low levels of HPyV-7 are shed from apparently normal skin, recent reports have described clinically significant cutaneous infection in immunocompromised patients that manifests as generalized pruritic plaques. The pruritus can be severe, and treatment options have not been described. Herein we report HPyV-7 cutaneous infection in a heart transplant patient who experienced temporary improvement with intravenous cidofovir, and complete remission with acitretin. We report a case of HPyV-7 cutaneous infection demonstrating a good response to treatment.

[Cutaneous infections: Pathologist's role in unusual or atypical situations]

In infectious pathology, the gold standard consists of the detection of the pathogen within the sample. Identification of the pathogen is often difficult despite the presence of few and inexpensive tools, such, as special stain, immunohistochemistry, or in situ hybridization specific of the pathogen. In infectious pathology, there are morphological signs, which can guide us towards an etiology. We present some clinicopathological examples illustrating rare or unusual situations in cutaneous infectious pathology.

Human polyomavirus 6 and 7 are associated with pruritic and dyskeratotic dermatoses

BACKGROUND

Human polyomavirus (HPyV)6 and HPyV7 are shed chronically from human skin. HPyV7, but not HPyV6, has been linked to a pruritic skin eruption of immunosuppression.

OBJECTIVE

We determined whether biopsy specimens showing a characteristic pattern of dyskeratosis and parakeratosis might be associated with polyomavirus infection.

METHODS

We screened biopsy specimens showing "peacock plumage" histology by polymerase chain reaction for HPyVs. Cases positive for HPyV6 or HPyV7 were then analyzed by immunohistochemistry, electron microscopy, immunofluorescence, quantitative polymerase chain reaction, and complete sequencing, including unbiased, next-generation sequencing.

RESULTS

We identified 3 additional cases of HPyV6 or HPyV7 skin infections. Expression of T antigen and viral capsid was abundant in lesional skin. Dual immunofluorescence staining experiments confirmed that HPyV7 primarily infects keratinocytes. High viral loads in lesional skin compared with normal-appearing skin and the identification of intact virions by both electron microscopy and next-generation sequencing support a role for active viral infections in these skin diseases.

LIMITATION

This was a small case series of archived materials.

CONCLUSION

We have found that HPyV6 and HPyV7 are associated with rare, pruritic skin eruptions with a distinctive histologic pattern and describe this entity as "HPyV6- and HPyV7-associated pruritic and dyskeratotic dermatoses."