Treating epidermolytic ichthyosis and ichthyosis with confetti with epidermal autografts cultured from revertant skin.

BACKGROUND: No efficient treatment has yet been established for epidermolytic ichthyosis (EI), which is caused by pathogenic variants of KRT1 or KRT10. Patients with ichthyosis with confetti (IWC) have multiple normal-appearing spots, caused by the revertant somatic recombination of pathogenic variants that occurs at each spot independently. Additionally, some patients with EI have large areas of normal skin due to revertant postzygotic mosaicism. OBJECTIVES: To assess the feasibility of transplanting cultured epidermal autografts (CEAs) produced from revertant epidermal keratinocytes in patients with EI and IWC. METHODS: We performed a clinical trial of treatment with CEAs produced from each patient's own revertant epidermal keratinocytes as a proof-of-concept study. This was a single-arm, open, unmasked, uncontrolled, single-assignment, treatment-purpose study. The primary outcome was the percentage area that lacked recurrence of ichthyosis lesions 4 weeks after the final transplant. The secondary outcome was the percentage area lacking recurrence of ichthyosis lesions 24 weeks after the initial transplantation. The trial was registered with the Japan Registry of Clinical Trials (jRCTb041190097). RESULTS: We successfully produced CEAs from genetically confirmed revertant skin from two patients with mosaic EI and from one patient with IWC and confirmed by amplicon sequencing and droplet digital polymerase chain reaction analysis that the CEAs mainly consisted of revertant wild-type cells. Single-cell RNA sequencing analysis confirmed the normal proliferation and safety profiling of CEAs. CEAs were transplanted onto desquamated lesional sites in the patients. Four weeks post-transplantation, the percentage area lacking recurrence of ichthyosis lesions in the three patients was 40%, 100% and 100% respectively, although recurrence of ichthyosis lesions was seen at the site of CEA transplantation in all three patients at 24 weeks post-transplantation. CONCLUSIONS: CEAs from normal skin have the potential to be a safe and local treatment option for EI and IWC.

Epidermolytic ichthyosis is a rare skin condition that causes redness, blistering and thickening of the skin. There is currently no effective treatment for the disease, which is caused by mutations in the genes KRT1 or KRT10. People with a type of the disease called 'ichthyosis with confetti' have many normal-appearing spots that are caused by the natural repair of the gene mutations. Some people with epidermolytic ichthyosis have large areas of healthy skin as a result of genetic mutations having been corrected. In this study, we successfully produced skin grafts from the healthy skin of two patients with epidermolytic ichthyosis and one with 'ichthyosis with confetti'. We confirmed that the skin grafts mainly consisted of repaired skin cells. A technique called 'single-cell RNA sequencing' confirmed the skin cells in the skin grafts behaved like healthy skin cells and that the grafts were safe. Overall, our study findings suggest that skin grafts taken from skin consisting of genetically normal keratinocytes that have undergone self-repair have potential to be a safe treatment option for patients with severe epidermolytic ichthyosis and 'ichthyosis with confetti'.

Epidermal nevi and epidermolytic hyperkeratosis: A review of cases, highlighting indications for biopsy and genetics referral.

Epidermal nevi are common benign cutaneous hamartomas that may rarely demonstrate histopathologic evidence of epidermolytic hyperkeratosis (EHK), representing cutaneous mosaicism for pathogenic keratin variants. Rarely, individuals with linear epidermal nevi transmit to their children the inherited form of EHK, also known as epidermolytic ichthyosis, characterized by generalized erythema, blistering, and scaling at birth evolving to widespread hyperkeratosis. We present an updated review of reported cases of linear epidermal nevi with EHK exhibiting transmission of epidermolytic ichthyosis to guide important considerations in the care of individuals with epidermal nevi. Clinical characteristics of linear epidermal nevi do not reliably predict the presence of EHK. All reported cases of transmission to offspring have occurred in individuals with linear epidermal nevi involving more than one anatomic area suggesting increased reproductive risk with involvement of two or more anatomic sites. Therefore, genetics consultation is recommended for these individuals with biopsy-confirmed EHK. For individuals with smaller areas of epidermal nevus involvement, the implications are less well known, though genetics consultation may still be considered for those interested in further discussion of general reproductive risk.

Epidermolytic Hyperkeratosis in an Epidermoid (Infundibular) Cyst.

ABSTRACT: Epidermolytic hyperkeratosis (EHK) is an uncommon histopathologic reaction pattern that may represent a primary pathological process or a coincidental finding in a variety of neoplasms. We present a case of EHK in an epidermoid (infundibular) cyst. Histopathologically, EHK demonstrates vacuolar degeneration of keratinocytes in the spinous and granular cell layers, with disrupted cellular boundaries, enlarged basophilic keratohyalin-like granules and amorphous eosinophilic inclusions, along with massive hyperkeratosis. In addition to the morphologic description of EHK, we summarize the diagnoses in which EHK has been reported. Prior cases of EHK in an epidermoid (infundibular) cyst are summarized to compare findings. The significance of incidental EHK in skin lesions is unknown.

High-fat diet induces a predisposition to follicular hyperkeratosis and neutrophilic folliculitis in mice.

BACKGROUND: Neutrophilic folliculitis is an inflammatory condition of hair follicles. In some neutrophilic folliculitis, such as in patients with acne and hidradenitis suppurativa, follicular hyperkeratosis is also observed. Neutrophilic folliculitis is often induced and/or exacerbated by a high-fat diet (HFD). However, the molecular mechanisms by which an HFD affects neutrophilic folliculitis are not fully understood. OBJECTIVE: Our aim was to elucidate how an HFD promotes the development of neutrophilic folliculitis. METHODS: Mice were fed an HFD, and their skin was subjected to histologic, RNA sequencing, and imaging mass spectrometry analyses. To examine the effect of an HFD on neutrophil accumulation around the hair follicles, phorbol 12-myristate 13-acetate (PMA) was used as an irritant to the skin. RESULTS: Histologic analysis revealed follicular hyperkeratosis in the skin of HFD-fed mice. RNA sequencing analysis showed that genes related to keratinization, especially in upper hair follicular keratinocytes, were significantly upregulated in HFD-fed mice. Application of PMA to the skin induced neutrophilic folliculitis in HFD-fed mice but not in mice fed a normal diet. Accumulation of neutrophils in the skin and around hair follicles was dependent on CXCR2 signaling, and CXCL1 (a CXCR2 ligand) was produced mainly by hair follicular keratinocytes. Imaging mass spectrometry analysis revealed an increase in fatty acids in the skin of HFD-fed mice. Application of these fatty acids to the skin induced follicular hyperkeratosis and caused PMA-induced neutrophilic folliculitis even in mice fed a normal diet. CONCLUSION: An HFD can facilitate the development of neutrophilic folliculitis with the induction of hyperkeratosis of hair follicles and increased neutrophil infiltration around the hair follicles via CXCR2 signaling.

An unusual case of keratinopathic icthyosis: a diagnostic conundrum.

Epidermolytic ichthyosis (EI) is a rare inherited ichthyosis related to heterozygous mutations in the Keratin 1 or Keratin 10 genes. Because of the broad phenotypic spectrum, it is sometimes difficult to differentiate it from other keratinopathic ichthyoses (KI) in clinical practice. We report an intriguing case of KI presenting as generalized ichthyosis in a reticulate pattern surrounding islands of normal skin, epidermolytic hyperkeratosis and binucleate cells on histopathology, and heterozygous mutation in KRT10. Through this case, we would like to demonstrate the importance of genetic studies and genotype-phenotype correlation in diagnosing such challenging cases.

Epidermolytic hyperkeratosis of the vulva.

Vulvar epidermolytic hyperkeratosis is a benign entity that mimics other malignant and inflammatory vulvar dermatoses clinically and histologically requiring careful clinical pathologic correlation for diagnosis.

Multiple Epidermolytic Acanthomas: Rare Vulval Lesions Which May be Mistaken for Viral Warts.

Epidermolytic acanthoma is a rare benign lesion that most often presents as a solitary or multiple small papular lesions on the trunk, face, limbs or external male genitalia. Only a small number of cases have been reported occurring on the vulva and clinically and histologically they may mimic and be misdiagnosed as viral warts. We report 2 cases of multiple epidermolytic acanthomas localized to the vulva. Molecular tests (in situ hybridization and polymerase chain reaction) showed no evidence of human papillomavirus infection and p16 staining was negative. We stress the need for pathologists to consider epidermolytic acanthoma in the differential diagnosis of multiple vulval lesions resembling viral warts.

Epidermolytic acanthoma in a young woman: a case letter.

Epidermolytic acanthoma (EA) is a rare benign tumor that is characterized by epidermolytic hyperkeratosis on histopathology. It usually presents in adulthood as an asymptomatic tumor <1 cm in diameter with a verrucous surface. We report a very uncommon case of epidermolytic acanthoma. A 21-year-old woman came to our hospital with a pale black papule on the left lower eyelid near the Inner canthus for 2 months. Two months ago the patient noted a pale brown spot on the inside of the left lower eyelid, which gradually enlarged, forming a papule with a deepened color. There were no associated symptoms, such as itching or pain. There were no local injuries, scratches, or other incidents before the crash occurred. The patient was always healthy, with no history of chronic disease or other skin diseases, and no similar cases existed in the family. We diagnosed it as EA.

Mutations in KRT10 in epidermolytic acanthoma.

BACKGROUND: Epidermolytic acanthoma (EA) is a rare acquired lesion demonstrating a characteristic histopathological pattern of epidermal degeneration referred to as epidermolytic hyperkeratosis (EHK). On histopathological analysis, EA appears nearly identical to inherited EHK-associated dermatoses such as epidermolytic ichthyosis and ichthyosis bullosa of Siemens. While it has been speculated that EA is caused by mutations in KRT10, KRT1, or KRT2 found in these inherited dermatoses, none have yet been identified. Herein, we aim to identify the contributions of keratin mutations to EA. METHODS: Using genomic DNA extracted from paraffin-embedded samples from departmental archives, we evaluated a discovery cohort using whole-exome sequencing (WES) and assessed remaining samples using Sanger sequencing screening and restriction fragment length polymorphism (RFLP) analysis. RESULTS: DNA from 16/20 cases in our sample was of sufficient quality for polymerase chain reaction amplification. WES of genomic DNA from lesional tissue revealed KRT10 c.466C > T, p.Arg156Cys mutations in 2/3 samples submitted for examination. RFLP analysis of these samples as well as eight additional samples confirmed the mutations identified via WES and identified four additional cases with Arg156 mutations. In sum, 6/11 screened cases showed hotspot mutation in KRT10. CONCLUSIONS: Hotspot mutations in the Arg156 position of KRT10, known to cause epidermolytic ichthyosis, also underlie EA.

First Case of KRT2 Epidermolytic Nevus and Novel Clinical and Genetic Findings in 26 Italian Patients with Keratinopathic Ichthyoses.

Keratinopathic ichthyoses (KI) are a clinically heterogeneous group of keratinization disorders due to mutations in KRT1, KTR10, or KRT2 genes encoding keratins of suprabasal epidermis. Characteristic clinical features include superficial blisters and erosions in infancy and progressive development of hyperkeratosis. Histopathology shows epidermolytic hyperkeratosis. We describe the clinical, histopathological, and molecular findings of a series of 26 Italian patients from 19 unrelated families affected with (i) epidermolytic ichthyosis due to KRT1 or KRT10 mutations (7 and 9 cases, respectively); (ii) KTR10-mutated ichthyosis with confetti (2 cases); (iii) KRT2-mutated superficial epidermolytic ichthyosis (5 cases); and (iv) KRT10-mutated epidermolytic nevus (2 cases). Of note, molecular genetic testing in a third case of extensive epidermolytic nevus revealed a somatic missense mutation (p.Asn186Asp) in the KRT2 gene, detected in DNA from lesional skin at an allelic frequency of 25% and, at very low frequency (1.5%), also in blood. Finally, we report three novel dominant mutations, including a frameshift mutation altering the C-terminal V2 domain of keratin 1 in three familiar cases presenting a mild phenotype. Overall, our findings expand the phenotypic and molecular spectrum of KI and show for the first time that epidermolytic nevus can be due to somatic KRT2 mutation.

TNF Is Partially Required for Cell-Death-Triggered Skin Inflammation upon Acute Loss of cFLIP.

cFLIP is required for epidermal integrity and skin inflammation silencing via protection from TNF-induced keratinocyte apoptosis. Here, we generated and analyzed cFLIP epidermal KO mice with additional TNF deficiency. Intriguingly, the ablation of TNF rescued the pathological phenotype of epidermal cFLIP KO from characteristic weight loss and increased mortality. Moreover, the lack of TNF in these animals strongly reduced and delayed the epidermal hyperkeratosis and the increased apoptosis in keratinocytes. Our data demonstrate that TNF signaling in cFLIP-deficient keratinocytes is the critical factor for the regulation of skin inflammation via modulated cytokine and chemokine expression and, thus, the attraction of immune cells. Our data suggest that autocrine TNF loop activation upon cFLIP deletion is dispensable for T cells, but is critical for neutrophil attraction. Our findings provide evidence for a negative regulatory role of cFLIP for TNF-dependent apoptosis and partially for epidermal inflammation. However, alternative signaling pathways may contribute to the development of the dramatic skin disease upon cFLIP deletion. Our data warrant future studies of the regulatory mechanism controlling the development of skin disease upon cFLIP deficiency and the role of cFLIP/TNF in a number of inflammatory skin diseases, including toxic epidermal necrolysis (TEN).

A de novo mutation of KRT1 in a baby girl causing epidermolytic ichthyosis with impressive epidermolytic palmoplantar keratoderma.

We report a 6-year-old girl showing epidermolytic ichthyosis/epidermolytic hyperkeratosis (EI/EH). Targeted Next Generation Sequencing revealed a de novo, previously unidentified KRT1 mutation. The findings of this study expands the clinical and  spectrum and genotype-phenotype correlation associated with EI/EH.

Solitary and multiple epidermolytic acanthoma: A demographic and clinical study of 131 cases.

BACKGROUND: Epidermolytic acanthoma (EA) is a rare, benign acquired cutaneous keratosis displaying epidermolytic hyperkeratosis in more than 50% of its surface. Because of the sparsity of comprehensive studies, little is known on the patient demographics and clinical characteristics of this uncommon entity. We wish to comprehensively characterize the clinical and demographic features of EA and to differentiate it from its mimickers. METHODS: We carried out a retrospective review of 131 cases of EA, recorded clinical and histopathologic features and performed linear regression of yearly incidence rates to assess for possible under-reporting of this entity. RESULTS: EA affected both genders equally. We found 9.08 cases per 100 000 biopsy specimens per year and linear regression analysis showed significantly decreasing incidence rates. Analysis of the anatomical site distribution of EA lesions showed a more frequent genital location in men (39.1% of cases in men, as compared to 11.3% for women). Contrary to previous studies, lesions were most frequently single (91.7%) and the mean age of presentation was 57.8 years. CONCLUSION: The presented largest case series to-date indicates that EA is probably an underdiagnosed entity and establishes the demographic and clinical features of EA.

Late-Onset Nevus Comedonicus With Follicular Epidermolytic Hyperkeratosis-Case Report and Review of the Literature.

Nevus comedonicus is a rare cutaneous follicular hamartoma, characterized by the clustering of papules with firm, blackened horny buffers. It is usually present at birth or during childhood, although few cases of late-onset disease have been described. We present a case of postmenopausal-onset nevus comedonicus in a 55-year-old white woman without relevant medical history. Skin biopsy showed the typical features of several cyst-dilated follicular structures occupied by keratotic material and the peculiar finding of epidermolytic hyperkeratosis of the follicular epithelial walls. A brief review of the clinical and histological features of other similar cases published in the literature is performed.

Recessive epidermolytic ichthyosis results from loss of keratin 10 expression, regardless of the mutation location.

Epidermolytic ichthyosis (EI) is a rare skin disorder caused by mutations in the genes KRT1 and KRT10, and is usually inherited in an autosomal dominant fashion. Only five recessive mutations causing EI have been described, all of which are located in the central region of the KRT10 gene. In the current study, we aimed to identify the genetic defect underlying EI in a 12-year-old patient. Direct sequencing of the patient's genomic DNA revealed a novel homozygous nonsense mutation residing within the proximal part KRT10 first exon. The mutation was found to co-segregate with the disease phenotype in an autosomal recessive fashion. Using real-time quantitative PCR, we found an almost two-fold decrease in KRT10 expression in the patient's skin compared with the skin of healthy controls. Western blot analysis showed complete absence of keratin 10 protein in the patient's skin, suggesting early protein degradation.

A novel association of pseudoainhum and epidermolytic ichthyosis, successfully treated with full thickness skin graft after failed z-plasty repair.

Pseudoainhum is a rare constriction band variant thatmay progress to spontaneous digital strangulationand auto-amputation. Although its association withpalmoplantar keratodermas is well established, ithas not been reported in conjunction with classicepidermolytic ichthyosis. We describe the first suchcase in a 25-year-old woman who presented witha painful constricting band of the fifth toe. We alsodescribe her treatment course, which consisted ofa failed z-plasty, the traditional therapeutic optionfor acute pseudoainhum, and report the success ofsubsequent full thickness skin graft, suggesting thebenefit of this procedure as a therapeutic alternativefor patients with pseudoainhum.

Epidermolytic Ichthyosis Sine Epidermolysis.

Epidermolytic ichthyosis (EI) is a rare disorder of cornification caused by mutations in KRT1 and KRT10, encoding two suprabasal epidermal keratins. Because of the variable clinical features and severity of the disease, histopathology is often required to correctly direct the molecular analysis. EI is characterized by hyperkeratosis and vacuolar degeneration of the upper epidermis, also known as epidermolytic hyperkeratosis, hence the name of the disease. In the current report, the authors describe members of 2 families presenting with clinical features consistent with EI. The patients were shown to carry classical mutations in KRT1 or KRT10, but did not display epidermolytic changes on histology. These observations underscore the need to remain aware of the limitations of pathological features when considering a diagnosis of EI.

Use of the frozen section 'jelly-roll' technique to aid in the diagnosis of bullous congenital ichthyosiform erythroderma (epidermolytic hyperkeratosis).

Frozen section is a valuable tool that is often underutilized in the setting of in-patient dermatology. Traditionally, frozen section has been used in dermatology to diagnose toxic epidermal necrolysis, with some additional utility in staphylococcal scalded skin syndrome in the new born period. We report a newborn female with ruptured bullae on the face, chest, back and extremities with a clinical differential diagnosis that included staphylococcal scalded skin, bullous congenital ichthyosiform erythroderma/epidermolytic hyperkeratosis and epidermolysis bullosa. A thin detached skin sample ('jelly-roll') taken from a ruptured bulla on the abdomen was prepared for frozen section analysis. Characteristic findings of epidermolytic hyperkeratosis were seen which included hyperkeratosis with granular layer degeneration, vacuolization and eosinophilic globules. The 'jelly-roll' technique can be used for quick diagnosis with minimal trauma to the patient. Epidermolytic hyperkeratosis was subsequently confirmed by a biopsy fixed in formalin and by genetic testing. A novel missense mutation in KRT1 (I479N) was identified. Herein, we discuss the use of the frozen section 'jelly roll' technique for rapid diagnosis in a case of bullous congenital ichthyosis erythroderma/epidermolytic hyperkeratosis.