Ageing is associated with a reduction in markers of mitochondrial energy metabolism in the human epidermis.

The decline of mitochondrial function throughout the lifespan is directly linked to the development of ageing phenotypes of the skin. Here, we assessed alterations in markers of epidermal mitochondrial energy metabolism as a function of skin age. Human skin samples from distinct anatomical regions were obtained during routine dermatological surgery from 21 young (27.6 ± 1.71 year) and 22 old (76.2 ± 1.73 year) donors. Sections of skin samples were analysed by immunohistochemistry for mitochondrial subunits of each electron transport chain complex (I-V)/oxidative phosphorylation (OXPHOS), as well as proteins serving as a marker of mitochondrial mass (VDAC1) and the regulation of DNA transcription (TFAM). Staining intensities of ATP5F1A (comprising complex V) and TFAM in the epidermis of older subjects were significantly decreased compared with younger donors. Moreover, these effects were independent of UV exposure of the stained skin section. Overall, we demonstrate that ageing is associated with reduced protein levels of complex V of the mitochondrial respiratory chain and TFAM. These alterations may impair essential mitochondrial functions, exacerbating the cutaneous ageing process.

The role of cyclin D1 and Ki-67 in the development and prognostication of thin melanoma.

AIMS: Despite their low individual metastatic potential, thin melanomas (≤1 mm Breslow thickness) contribute significantly to melanoma mortality overall. Therefore, identification of prognostic biomarkers is particularly important in this subgroup of melanoma. Prompted by preclinical results, we investigated cyclin D1 protein and Ki-67 expression in in-situ, metastatic and non-metastatic thin melanomas. METHODS AND RESULTS: Immunohistochemistry was performed on 112 melanoma specimens, comprising 22 in situ, 48 non-metastatic and 42 metastatic thin melanomas. Overall, epidermal and dermal cyclin D1 and Ki-67 expression were semiquantitatively evaluated by three independent investigators and compared between groups. Epidermal Ki-67 expression did not differ statistically in in-situ and invasive melanoma (P = 0.7). Epidermal cyclin D1 expression was significantly higher in thin invasive than in in-situ melanoma (P = 0.003). No difference was found in cyclin D1 expression between metastatic and non-metastatic invasive tumours. Metastatic and non-metastatic thin melanomas did not show significant differences in epidermal expression of Ki-67 and cyclin D1 (P = 0.148 and P = 0.611, respectively). In contrast, strong dermal expression of Ki-67 was more frequent in metastatic than non-metastatic samples (28.6 versus 8.3%, respectively, P = 0.001). The prognostic value of dermal Ki-67 expression was confirmed by multivariate analysis (P = 0.047). CONCLUSION: We found an increased expression of cyclin D1 in invasive thin melanomas compared to in-situ melanomas, which supports a potential role of this protein in early invasion in melanoma, as suggested by preclinical findings. Moreover, our results confirm that high dermal Ki-67 expression is associated with an increased risk of development of metastasis in thin melanoma and could possibly serve as a prognostic biomarker in clinical practice, especially if combined with additional methods.

Melanoma tumors exhibit a variable but distinct metabolic signature.

The Warburg theory of cancer postulates that an important driver of tumorigenesis is insufficient respiration due to mitochondrial defects, and concomitant enhancement of lactate production due to increased aerobic glycolysis. We analysed 48 melanoma samples by immunohistochemistry and found that 38% of melanomas are characterized by areas of isolated or combined deficiencies of complexes of the oxidative phosphorylation (OXPHOS) system, whereby the incidence of OXPHOS-deficient areas is associated with an increased Breslow index; 62% of melanomas showed high expression of all OXPHOS complexes. Expression of carbonic anhydrase IX was low, indicating that melanomas generally are well-oxygenated. Expression of HIF-1α and MCT4 was high, which might be a consequence of increased lactate dehydrogenase A levels in melanomas. Our data indicate that there are two types of melanomas: one that features a classic Warburg effect, whereas the other one, despite being glycolytic, maintains a high level of OXPHOS complexes.

SF3B1 and BAP1 mutations in blue nevus-like melanoma.

Blue nevi are melanocytic tumors originating in the cutaneous dermis. Malignant tumors may arise in association with or resembling blue nevi, so called 'blue nevus-like melanoma', which can metastasize and result in patient death. Identifying which tumors will behave in a clinically aggressive manner can be challenging. Identifying genetic alterations in such tumors may assist in their diagnosis and prognostication. Blue nevi are known to be genetically related to uveal melanomas (eg, both harboring GNAQ and GNA11 mutations). In this study, we analyzed a large cohort (n=301) of various morphologic variants of blue nevi and related tumors including tumors diagnosed as atypical blue nevi (n=21), and blue nevus-like melanoma (n=12), screening for all gene mutations known to occur in uveal melanoma. Similar to published reports, we found the majority of blue nevi harbored activating mutations in GNAQ (53%) or GNA11 (15%). In addition, rare CYSLTR2 (1%) and PLCB4 (1%) mutations were identified. EIF1AX, SF3B1, and BAP1 mutations were also detected, with BAP1 and SF3B1 R625 mutations being present only in clearly malignant tumors (17% (n=2) and 25% (n=3) of blue nevus-like melanoma, respectively). In sequencing data from a larger cohort of cutaneous melanomas, this genetic profile was also identified in tumors not originally diagnosed as blue nevus-like melanoma. Our findings suggest that the genetic profile of coexistent GNAQ or GNA11 mutations with BAP1 or SF3B1 mutations can aid the histopathological diagnosis of blue nevus-like melanoma and distinguish blue nevus-like melanoma from conventional epidermal-derived melanomas. Future studies will need to further elucidate the prognostic implications and appropriate clinical management for patients with tumors harboring these mutation profiles.

Annular Lichenoid Dermatitis (of Youth) Immunohistochemical and Serological Evidence for Another Clinical Presentation of Borrelia Infection in Patients of Western Austria.

Annular lichenoid dermatitis of youth (ALDY) is a more recently described inflammatory disease of the skin of unknown etiology with clinical similarities to morphea. The authors clinically, histopathologically, and immunohistochemically investigated 14 biopsies from 12 patients in western Austria with this disease. There were 6 female and 6 male patients with solitary (n = 7) and multiple lesions (n = 5) affecting the trunk (n = 11), upper arm (n = 2), thigh (n = 1), and calf (n = 1). Clinically, early lesions were erythematous in nature leading to central paleness, scaling, wrinkling, dermal atrophy, slight pigmentation, and telangiectasia later on. Histopathologically, all specimens showed the typical features of ALDY with a superficial lichenoid process with sprinkling of lymphocytes along the basal cell layer and within the epidermis accompanied by mild fibrosis. Pigment incontinence, superficial fibrosis, and dilatation of superficial capillary vessels are prominent features in more advanced stages of disease. Immunohistologically, using a polyclonal antibody against Borrelia, 11/14 specimens revealed spirochetes, either vital (n = 4) or degenerated (n = 7), in close proximity to collagen bundles. Thirteen of 14 specimens in addition showed focal (n = 4) or clustered (n = 9) positivity for CD20 in the papillary dermis. Nine of 12 sera tested for Borrelia with an enzyme-linked immunosorbent assay were positive. Lichen sclerosus et atrophicus and morphea have previously been reported to be possibly related to Borrelia infection. We postulate that a similar relationship to Borrelia infection may be true for ALDY implying that ALDY may be an early superficial stage of morphea.

Deep learning based histological classification of adnex tumors.

BACKGROUND: Cutaneous adnexal tumors are a diverse group of tumors arising from structures of the hair appendages. Although often benign, malignant entities occur which can metastasize and lead to patients´ death. Correct diagnosis is critical to ensure optimal treatment and best possible patient outcome. Artificial intelligence (AI) in the form of deep neural networks has recently shown enormous potential in the field of medicine including pathology, where we and others have found common cutaneous tumors can be detected with high sensitivity and specificity. To become a widely applied tool, AI approaches will also need to reliably detect and distinguish less common tumor entities including the diverse group of cutaneous adnexal tumors. METHODS: To assess the potential of AI to recognize cutaneous adnexal tumors, we selected a diverse set of these entities from five German centers. The algorithm was trained with samples from four centers and then tested on slides from the fifth center. RESULTS: The neural network was able to differentiate 14 different cutaneous adnexal tumors and distinguish them from more common cutaneous tumors (i.e. basal cell carcinoma and seborrheic keratosis). The total accuracy on the test set for classifying 248 samples into these 16 diagnoses was 89.92 %. Our findings support AI can distinguish rare tumors, for morphologically distinct entities even with very limited case numbers (< 50) for training. CONCLUSION: This study further underlines the enormous potential of AI in pathology which could become a standard tool to aid pathologists in routine diagnostics in the foreseeable future. The final diagnostic responsibility will remain with the pathologist.

Novel and recurrent germline and somatic mutations in a cohort of 67 patients from 48 families with Brooke-Spiegler syndrome including the phenotypic variant of multiple familial trichoepitheliomas and correlation with the histopathologic findings in 379 biopsy specimens.

Brooke-Spiegler syndrome (BSS) is a rare, inherited, autosomal dominant disorder characterized by development of multiple adnexal cutaneous neoplasms including spiradenoma, cylindroma, spiradenocylindroma, and trichoepithelioma. The syndrome of multiple familial trichoepitheliomas (MFT) is considered a phenotypic variant of BSS in which patients present with trichoepitheliomas only. We studied germline and somatic mutations of the CYLD gene by direct sequencing in patients with BSS (n = 49) and MFT (n = 18) using peripheral blood and 90 samples of frozen or formalin-fixed paraffin-embedded tumor tissue selected from 379 available histology specimens. Germline CYLD mutations were found in 51 patients (76%) from 36 families (75%). Germline CYLD mutations were found in 43 of the 49 patients with BSS (88%) but in only 8 of 18 MFT cohort (44%). Twenty-one frameshift, 15 nonsense, 3 missense, and 4 splice site mutations were found in patients with BSS, whereas 1 frameshift, 5 nonsense, and 2 splice site mutations were identified in the MFT cohort. Five novel mutations were identified including 4 frameshift mutations (c.1027dupA/p.T343NfsX7, c.2155dupA/p.M719NfsX5, c.2288_2289delTT/p.F763X, and c.2641delG/p.D881TfsX32) and 1 nonsense mutation (c.2713C>T/p. Q905X). Of the 76 tumors from 32 patients with a germline CYLD mutation, 12 were spiradenomas, 15 spiradenocylindromas, 26 cylindromas, 15 trichoepitheliomas, and 7 were other tumor types. Somatic mutations were detected in 67 specimens of these 76 tumors (88%). Of the 67 somatic mutations, 21 (31%) represented a sequence alteration and 46 (69%) showed loss of heterozygosity. In the remaining 9 cases (12%), the somatic changes remained unknown. A germline CYLD mutation was not detected in 14 tumor samples from 8 patients. In these 14 tumors, somatic mutations were identified in 6 samples (43%), all consisting of sequence alterations (1 sample showed 2 different sequence alterations). In the remaining 8 samples (53%), neither germline nor somatic mutations were found in the lesional tissue. Our study increases the catalog of known CYLD mutations in patients with BSS/MFT to 86 and documents the variability of somatic mutations that may occur in them. We confirm the absence of firm genotype-phenotype correlations and the existence of a subset of patients with BSS/MFT who lack a demonstrable germline CYLD mutation. Further studies are needed to explain the reasons for this phenomenon.

Ketogenic diets slow melanoma growth in vivo regardless of tumor genetics and metabolic plasticity.

BACKGROUND: Growing evidence supports the use of low-carbohydrate/high-fat ketogenic diets as an adjunctive cancer therapy. However, it is unclear which genetic, metabolic, or immunological factors contribute to the beneficial effect of ketogenic diets. Therefore, we investigated the effect of ketogenic diets on the progression and metabolism of genetically and metabolically heterogeneous melanoma xenografts, as well as on the development of melanoma metastases in mice with a functional immune system. METHODS: Mice bearing BRAF mutant, NRAS mutant, and wild-type melanoma xenografts as well as mice bearing highly metastatic melanoma allografts were fed with a control diet or ketogenic diets, differing in their triglyceride composition, to evaluate the effect of ketogenic diets on tumor growth and metastasis. We performed an in-depth targeted metabolomics analysis in plasma and xenografts to elucidate potential antitumor mechanisms in vivo. RESULTS: We show that ketogenic diets effectively reduced tumor growth in immunocompromised mice bearing genetically and metabolically heterogeneous human melanoma xenografts. Furthermore, the ketogenic diets exerted a metastasis-reducing effect in the immunocompetent syngeneic melanoma mouse model. Targeted analysis of plasma and tumor metabolomes revealed that ketogenic diets induced distinct changes in amino acid metabolism. Interestingly, ketogenic diets reduced the levels of alpha-amino adipic acid, a biomarker of cancer, in circulation to levels observed in tumor-free mice. Additionally, alpha-amino adipic acid was reduced in xenografts by ketogenic diets. Moreover, the ketogenic diets increased sphingomyelin levels in plasma and the hydroxylation of sphingomyelins and acylcarnitines in tumors. CONCLUSIONS: Ketogenic diets induced antitumor effects toward melanoma regardless of the tumors´ genetic background, its metabolic signature, and the host immune status. Moreover, ketogenic diets simultaneously affected multiple metabolic pathways to create an unfavorable environment for melanoma cell proliferation, supporting their potential as a complementary nutritional approach to melanoma therapy.

Deep Learning Assisted Diagnosis of Onychomycosis on Whole-Slide Images.

BACKGROUND: Onychomycosis numbers among the most common fungal infections in humans affecting finger- or toenails. Histology remains a frequently applied screening technique to diagnose onychomycosis. Screening slides for fungal elements can be time-consuming for pathologists, and sensitivity in cases with low amounts of fungi remains a concern. Convolutional neural networks (CNNs) have revolutionized image classification in recent years. The goal of our project was to evaluate if a U-NET-based segmentation approach as a subcategory of CNNs can be applied to detect fungal elements on digitized histologic sections of human nail specimens and to compare it with the performance of 11 board-certified dermatopathologists. METHODS: In total, 664 corresponding H&E- and PAS-stained histologic whole-slide images (WSIs) of human nail plates from four different laboratories were digitized. Histologic structures were manually annotated. A U-NET image segmentation model was trained for binary segmentation on the dataset generated by annotated slides. RESULTS: The U-NET algorithm detected 90.5% of WSIs with fungi, demonstrating a comparable sensitivity with that of the 11 board-certified dermatopathologists (sensitivity of 89.2%). CONCLUSIONS: Our results demonstrate that machine-learning-based algorithms applied to real-world clinical cases can produce comparable sensitivities to human pathologists. Our established U-NET may be used as a supportive diagnostic tool to preselect possible slides with fungal elements. Slides where fungal elements are indicated by our U-NET should be reevaluated by the pathologist to confirm or refute the diagnosis of onychomycosis.

Multiple (familial) trichoepitheliomas: a clinicopathological and molecular biological study, including CYLD and PTCH gene analysis, of a series of 16 patients.

Multiple familial trichoepitheliomas (MFT) constitute an autosomally inherited syndrome possibly related to Brooke-Spiegler syndrome (BSS). Although some early studies suggested a role for the PTCH gene on chromosome 9q22.3 in the etiopathogenesis of MFT, recent studies of occasional patients with the MFT clinical phenotype identified mutations in the CYLD gene on chromosome 16q12-q13, a gene responsible for BSS. A systematic investigation of PTCH and CYLD mutations in patients with MFT has never been performed. Our main objective was to collect a reasonably large series of patients with MFT to (1) study the clinicopathological spectrum of the disease, (2) determine whether the PTCH gene is implicated in the pathogenesis of MFT, and if so (3) determine the relative frequency of CYLD and PTCH mutations, (4) establish if there may be any possible genotype-phenotype correlations, and (5) study the spectrum of somatic mutations. Clinical analysis including family histories, histopathological investigations, and molecular genetic studies were performed. There were 9 female and 7 male patients ranging in age from 11 to 63 years. They presented with multiple, small, discrete and sometimes confluent, skin-colored to pink, asymptomatic nodules preferentially located on the face, being especially prominent and confluent in the nasolabial folds and inner aspects of the eyebrows. A total of 66 conventional trichoepitheliomas (TEs) were studied microscopically. Aside from typical features of TE, some also exhibited variant morphological patterns including areas reminiscent of other benign adnexal neoplasms and melanocytic hyperplasia. In none of the 9 patients tested was a germline mutation of the PTCH gene identified. Germline CYLD mutations were detected in 6 of 13 patients tested (identical in 2 unrelated patients) including 2 novel mutations, whereas the remaining 7 individuals showed wild-type alleles. Two patients with germline wild-type CYLD showed, however, a somatic mutation in the gene (1 duplication, 1 substitution mutation). Neither CYLD nor PTCH germline mutations were found in the 5 patients in whom both genes were analyzed. MFT seems to be a phenotypic variant of BSS. The PTCH gene is rarely, if ever, involved in the pathogenesis of MFT. Absence of a germline mutation of the CYLD gene in cases harboring a somatic mutation may be explained by large deletions in the gene or by mutation in intronic sequences or in the promoter region. Considering our 5 patients with no mutation in either gene, the final possibility is that another, as yet undescribed gene (neither CYLD nor PTCH) is implicated in the pathogenesis of some patients with MFT.

COVID-19-Induced Reduction in Primary Melanoma Diagnoses: Experience from a Dermatopathology Referral Center.

The collateral damage caused by COVID-19 pandemic-associated public health and governmental measures on patient care has been increasingly assessed in various oncological and non-oncological clinical settings. In order to investigate potential adverse effects in the field of melanoma the present study analyzed the characteristics of primary melanoma diagnoses at an Austrian dermato-pathological referral center before, during, and after the first coronavirus-related lockdown in March 2020. As suspected, we found significant temporary reductions in the number of newly diagnosed melanomas in 2020 compared to previous years, in particular, during the first lockdown period.

Targeted Metabolomics Identifies Plasma Biomarkers in Mice with Metabolically Heterogeneous Melanoma Xenografts.

Melanomas are genetically and metabolically heterogeneous, which influences therapeutic efficacy and contributes to the development of treatment resistance in patients with metastatic disease. Metabolite phenotyping helps to better understand complex metabolic diseases, such as melanoma, and facilitates the development of novel therapies. Our aim was to characterize the tumor and plasma metabolomes of mice bearing genetically different melanoma xenografts. We engrafted the human melanoma cell lines A375 (BRAF mutant), WM47 (BRAF mutant), WM3000 (NRAS mutant), and WM3311 (BRAF, NRAS, NF1 triple-wildtype) and performed a broad-spectrum targeted metabolomics analysis of tumor and plasma samples obtained from melanoma-bearing mice as well as plasma samples from healthy control mice. Differences in ceramide and phosphatidylcholine species were observed between melanoma subtypes irrespective of the genetic driver mutation. Furthermore, beta-alanine metabolism differed between melanoma subtypes and was significantly enriched in plasma from melanoma-bearing mice compared to healthy mice. Moreover, we identified beta-alanine, p-cresol sulfate, sarcosine, tiglylcarnitine, two dihexosylceramides, and one phosphatidylcholine as potential melanoma biomarkers in plasma. The present data reflect the metabolic heterogeneity of melanomas but also suggest a diagnostic biomarker signature for melanoma screening.

Galanin receptor 3 attenuates inflammation and influences the gut microbiota in an experimental murine colitis model.

The regulatory (neuro)peptide galanin and its three receptors (GAL1-3R) are involved in immunity and inflammation. Galanin alleviated inflammatory bowel disease (IBD) in rats. However, studies on the galanin receptors involved are lacking. We aimed to determine galanin receptor expression in IBD patients and to evaluate if GAL2R and GAL3R contribute to murine colitis. Immunohistochemical analysis revealed that granulocytes in colon specimens of IBD patients (Crohn's disease and ulcerative colitis) expressed GAL2R and GAL3R but not GAL1R. After colitis induction with 2% dextran sulfate sodium (DSS) for 7 days, mice lacking GAL3R (GAL3R-KO) lost more body weight, exhibited more severe colonic inflammation and aggravated histologic damage, with increased infiltration of neutrophils compared to wild-type animals. Loss of GAL3R resulted in higher local and systemic inflammatory cytokine/chemokine levels. Remarkably, colitis-associated changes to the intestinal microbiota, as assessed by quantitative culture-independent techniques, were most pronounced in GAL3R-KO mice, characterized by elevated numbers of enterobacteria and bifidobacteria. In contrast, GAL2R deletion did not influence the course of colitis. In conclusion, granulocyte GAL2R and GAL3R expression is related to IBD activity in humans, and DSS-induced colitis in mice is strongly affected by GAL3R loss. Consequently, GAL3R poses a novel therapeutic target for IBD.

Retiform hemangioendothelioma: presentation of a case expressing D2-40.

Retiform hemangioendothelioma (RH) is a low-grade angiosarcoma with low metastatic risk, usually occurring as a single lesion on the trunk or extremity in middle-aged adults. Histopathology shows a distinctive pattern with arborizing blood vessels arranged in a retiform pattern (similar to rete testis tissue) and focal papillae with fibrosclerotic (hyaline) cores. The blood vessels are lined by comparatively monomorphic endothelial cells, frequently presenting a hobnail pattern. We report a case of RH presenting as an indolent brownish plaque on the back of a 17-year-old male. Surgical resection and sentinel lymph node biopsy showed no evidence of metastasis. In contrast to the recent literature, this case of RH showed positivity for D2-40, a marker of lymphatic endothelium. We also report ultrastructural findings for this case of RH.

Vincristine, idarubicin, dexamethasone and thalidomide in scleromyxoedema.

Scleromyxoedema is a rare disease of unknown aetiology that is characterized by progressive cutaneous mucinosis and paraproteinaemia. A variety of systemic (e.g. gastro intestinal, neurological, pulmonary, cardiac and renal) complications may lead to significant morbidity and mortality necessitating therapeutic intervention. The latter remains challenging. Numerous treatment modalities have been reported in the literature, often, however, with inconsistent responses, frequent relapses and potentially serious side-effects. Moreover, the rarity of scleromyxoedema has prevented the execution of controlled therapeutic trials. This paper discusses current proposed therapeutic strategies and reports the case of a 64-year-old male patient with progressive scleromyxoedema associated with IgG-lambda paraproteinaemia in whom monthly administrations of vincristine, idarubicin and dexamethasone in addition to daily oral thalidomide led to clinical and laboratory remission within 12 weeks.

Galanin is a potent modulator of cytokine and chemokine expression in human macrophages.

The regulatory peptide galanin is broadly distributed in the central- and peripheral nervous systems as well as in non-neuronal tissues, where it exerts its diverse physiological functions via three G-protein-coupled receptors (GAL1-3-R). Regulatory peptides are important mediators of the cross-communication between the nervous- and immune systems and have emerged as a focus of new therapeutics for a variety of inflammatory diseases. Studies on inflammatory animal models and immune cells revealed both pro- and anti-inflammatory functions of galanin. Here, we probed specific immune-related functions of the galanin system and found galanin and GAL1-R and GAL2-R mRNA to be expressed in a range of human immune cells. In particular, macrophages displayed differentiation- and polarization-dependent expression of galanin and its receptors. Exposure to exogenous galanin affected the cytokine/chemokine expression profile of macrophages differently, depending on their differentiation and polarization, and mainly modulated the expression of chemokines (CCL2, CCL3, CCL5 and CXCL8) and anti-inflammatory cytokines (TGF-ß, IL-10 and IL-1Ra), especially in type-1 macrophages. Cytokine/chemokine expression levels in interferon-gamma- and lipopolysaccharide-polarized macrophages were upregulated whereas in unpolarized macrophages they were downregulated upon galanin treatment for 20 hours. This study illuminates the regulation of important cytokines/chemokines in macrophages by galanin, depending on specific cell activation.

Cytokeratin-related loss of cellular integrity is not a major driving force of human intrinsic skin aging.

The contribution of extracellular matrix components to intrinsic skin aging has been investigated thoroughly, however, there is little information as to the role of the cytoskeletal proteins in this process. Therefore, we compared the expression of the constituents of the cytoskeleton, keratins 1-23 (K1-K23) as well as junction-plakoglobin (JUP), alpha-tubulin (TUBA), and beta-actin (ACTB) in human foreskins of both young (mean 6.4 years) and aged (mean 54.3 years) individuals. By applying RNA expression analysis to intrinsically aged human skin, we demonstrated that the mRNA levels of the genes for K1, K3, K4, K9, K13, K15, K18, K19 and K20 are downregulated in aged skin, K5 and K14 are unchanged, and K2, K16 and K17 are upregulated in aged skin. The mRNA data were confirmed on the protein level. This diverse picture is in contrast to other cytoskeletal proteins including components of the desmosome (JUP), microtubuli (TUBA) and microfilaments (ACTB) - often regarded as house-keeping genes - that were all reduced in aged skin. These cytoskeletal features of intrinsic aging highlight the importance of the cellular compartment in this process and demonstrate that special attention has to be given to RNA as well as protein normalization in aging studies.

Apocrine mixed tumor of the skin ("mixed tumor of the folliculosebaceous-apocrine complex"). Spectrum of differentiations and metaplastic changes in the epithelial, myoepithelial, and stromal components based on a histopathologic study of 244 cases.

BACKGROUND: A systematic analysis of the entire spectrum of various forms of differentiation and metaplastic epiphenomena in cutaneous apocrine mixed tumor (AMT) has never been performed. OBJECTIVE: The purpose of our study was to study a large number of cutaneous mixed tumors so as to fully characterize the entire spectrum of differentiations and metaplastic changes that may occur in the epithelial, myoepithelial, and stromal components of AMT. METHODS: This article reports a light-microscopic study of 244 cases of cutaneous AMT, complemented by a literature review. RESULTS: All types of differentiation along the lines of the folliculosebaceous-apocrine unit can be seen in AMT. The spectrum of metaplastic changes in the epithelial components includes squamous metaplasia, mucinous metaplasia, oxyphilic metaplasia, clear cell change, columnar metaplasia, hobnail metaplasia, and cytoplasmic vacuolization. The following changes in the myoepithelial component were documented: clear cell change, hyaline cells, plasmacytoid cells, spindling, and collagenous spherulosis. Stromal alterations included chondroid metaplasia, osseous metaplasia, and adipose metaplasia. LIMITATIONS: This study utilizes tissue specimens that mainly came as consultations; therefore some inherent selection bias exists. CONCLUSIONS: AMT displays a wide range of differentiation and metaplastic changes in its epithelial, myoepithelial, and stromal components. These phenomena are not mutually exclusive. When unduly prominent, they may present diagnostic pitfalls. Our findings corroborate those of previous publications, stressing the remarkable diversity of differentiation and metaplasias that may be found in cutaneous AMT. We propose that the most appropriate name for these lesions is "mixed tumor of the folliculosebaceous-apocrine complex."

Copy number variations in atypical fibroxanthomas and pleomorphic dermal sarcomas.

Atypical fibroxanthomas (AFX) and pleomorphic dermal sarcomas (PDS) are frequent cutaneous sarcomas typically arising on sun-exposed skin in elderly patients. In contrast to AFX, which generally do not recur after complete excision, PDS locally recur in up to 50% and metastasize in up to 20%. We recently detected characteristic UV-induced TP53 mutations as potential driver mutation in almost all PDS investigated as well as activating PIK3CA and RAS gene mutations in around one third of our tumors representing targets for personalized treatments in patients with unresectable or metastasized PDS. In the present study, we identified amplifications and deletions in a small part of the PDS (6 of 27 cases) but not in AFX suggesting that copy number variations (CNV) might not be an initial event in tumor development but rather important during tumor progression. In addition to BRAF, KNSTRN, IDH1 and PDGFRA amplification, CNV analyses revealed deletions in the CDKN2A, KIT and PDGFRA genes. In cases where an appropriate FISH assay was established, the CNV results could be verified by FISH analysis. Amplification of BRAF, KIT or PDGFRA and/or losses of CDKN2A might represent bad prognostic markers, although larger studies are needed to clarify their association with prognosis or progression in PDS.

Ectopic apocrine glands as a predisposing factor for postinflammatory medial meatal fibrosis: a clinicopathologic study.

OBJECTIVE: To illuminate pathophysiologic processes in postinflammatory medial meatal fibrosis (PMMF), a rare otologic disease of unknown etiology, which is defined by a progressive, obliterating fibrosis that affects the osseous part of the external auditory canal (EAC) exclusively. STUDY DESIGN: Retrospective clinical and histopathologic study. SETTING: Tertiary referral center. PATIENTS: Eleven patients (4 female and 7 male subjects) who underwent surgery of the bony EAC due to PMMF (13 ears operated). METHODS: Histologic and immunohistochemical assessment of tissue specimens obtained during surgical excision. MAIN OUTCOME MEASURE: Detection of ectopic apocrine glands and concomitant inflammatory infiltrate within tissue harvested from the osseous EAC. RESULTS: Additionally to expected histologic findings, such as excessive fibrosis and a chronic inflammatory infiltrate, ectopic spread of apocrine glands was consistently detected in all of our patients. CONCLUSION: Based on our findings, we suggest that an ectopic occurrence of adnexal structures within the bony EAC may predispose susceptible individuals to the development of PMMF. To avoid postoperative recurrence due to iatrogenic spread of cutaneous adnexal structures during surgery, the split-thickness skin graft should not exceed a thickness of 0.4 mm.