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Abstract: According to guidelines published by the Infectious Disease Society of America, Lyme disease prophylaxis is possible if a tick can be identified as Ixodes scapularis (nymphal or adult) within 72 hours of tick removal. However, a recent survey of medical practitioners indicates generally poor proficiency in tick identification. In this study, we provide a simple, practical guide to aid medical practitioners in identifying the most commonly encountered human biting ticks of North America., Competing Interests: The authors declare no conflicts of interest., (Copyright © 2021 Wolters Kluwer Health, Inc. All rights reserved.)

Objectives: Prompt accurate identification of tick species is required for appropriate administration of single dose antimicrobial prophylaxis for Lyme disease in selected patients. To determine the proficiency of clinicians at tick identification in the northeastern United States where Lyme disease has its highest incidence, we undertook a survey., Methods: We analyzed the results of a voluntary survey testing proficiency in identifying tick species using high-resolution photographs of ticks., Results: Only 35% of ticks were correctly identified. Although 60% of respondents could identify a nonengorged adult blacklegged tick, only 34% could correctly identify a partially engorged blacklegged tick. Participants performed even worse at classifying brown dog, American dog, and Lone Star ticks., Conclusions: Proficiency of tick identification by pathologists and clinicians is poor., Competing Interests: The authors declare no conflicts of interest., (Copyright © 2021 Wolters Kluwer Health, Inc. All rights reserved.)

Objectives: Oral autoimmune bullous disorders show clinical overlap with diseases such as lichen planus and others that may cause desquamative gingivitis. As direct immunofluorescence is expensive, we sought to determine if routine histology alone would be sufficient to distinguish between oral autoimmune bullous disorders and mimics., Methods: We searched the records for patients with a suspected oral autoimmune bullous disorder who underwent biopsies for concurrent routine histologic evaluation and direct immunofluorescence and who had at least one follow-up visit. Cases were separated into high and low suspicion subgroups based on clinical findings., Results: Within 148 cases, the sensitivity of routine histology alone was 0.810, with a negative predictive value of 0.889. However, the specificity was 0.989 with a positive predictive value of 0.979. Of the high suspicion cases, 57 (47.1%) were found to be consistent with an oral autoimmune bullous disorder, with a total of 11 histologic false negatives. 8 cases, all in the high suspicion subgroup, showed indeterminate direct immunofluorescence results. There were no histologic false negatives or inconclusive direct immunofluorescence results in the low suspicion subgroup., Conclusions: In patients with a low clinical suspicion for an oral autoimmune bullous disorder, it is reasonable and more cost-effective to evaluate the lesion with routine histology alone., (© 2019 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd. All rights reserved.)

Ixazomib is a second-generation proteasome inhibitor that has been approved in the combination treatment of multiple myeloma and is currently under clinical investigation for the management of Waldenstrom's macroglobulinemia. While cutaneous adverse events secondary to proteasome inhibitors have been reported, the side effect profile of ixazomib remains to be documented. We report two patients, one with multiple myeloma and one with Waldenstrom's macroglobulinemia, who developed cutaneous necrotizing vasculitis after the initiation of ixazomib. Both patients exhibited no signs of systemic vasculitis and completed their anti-cancer regimens with resolution of their respective eruptions following dose reductions in ixazomib and initiation of low-dose prednisone. A collaborative effort towards the characterization of such cutaneous toxicities facilitates early intervention, maintenance of life-preserving anti-cancer therapy, and allows clinicians opportunity to better understand the pathophysiology of vasculitis. Moreover, appropriate identification and characterization of cutaneous toxicities from novel therapies allows providers to accurately identify safety concerns, treat toxicity, and improve patient quality of life.

The vast majority of vulvar human papilloma virus infections are produced by α human papilloma viruses and consist of exophytic or flat warts and classic or "usual" vulvar intraepithelial neoplasia. This report details 2 examples of epidermodysplasia verruciformis-like lesions of the vulva in women who were immunosuppressed. The most consistent morphologic feature was the presence of abnormal mature keratinocytes with large pale open nuclei with small nucleoli and eosinophilic cytoplasm, situated in the upper epithelial layers. In addition to these features, which are commonly seen in epidermodysplasia verruciformis-associated lesions, 1 case displayed in addition more extensively distributed abnormal nuclei, including involvement of both the upper epithelial strata and the epithelial/stromal interface. Both lesions were associated with β-papilloma virus type 5. The unique aspects of epidermodysplasia verruciformis-like lesions relative to the more common human papilloma virus infections of the vulva are highlighted and these cases illustrate the range of epithelial distribution that might be encountered in lesions involving the vulvar mucosa.

Necrotizing soft tissue infections are rare but are associated with high rates of morbidity and mortality. The use of bedside or intraoperative frozen sections has been reported to be associated with faster diagnosis and better outcomes; however, to date no large studies have been published to determine the sensitivity and specificity of frozen sections in this setting. Twenty years of cases suspicious for necrotizing soft tissue infection at a large academic referral center were reviewed, blinded to the final clinical diagnosis (gold standard). Cases were assessed for the number of neutrophils, extent of necrosis, presence of thrombi, bacteria, karyorrhexis, and fibrin, and concordance with permanent sections. A total of 166 cases suspicious for necrotizing soft tissue infection had frozen section slides available for review. Sixty-three cases were clinically determined to be positive and 103 negative. Neutrophils, necrosis, thrombi, bacteria, karyorrhexis, and fibrin were present in both positive and negative cases; however, no histological feature or combination of features was found to be both sensitive and specific for necrotizing soft tissue infection. The combined presence of necrosis and frequent neutrophils was 73% sensitive and 68% specific, with a 58% positive predictive value and 80% negative predictive value. The additional observation of bacteria decreased sensitivity to 32%, whereas raising specificity to 91%, with 69% positive predictive value and 68% negative predictive value. Thirty-two cases (19%) contained findings identified on permanent sections (eg, bacteria) not observed on frozen section slides, highlighting the risk of false negatives owing to technical limitations or sampling errors. Frozen sections in necrotizing soft tissue infections and negative cases may show similar histological findings. Combined with the risk of false negatives, these results suggest that frozen sections are likely to be of limited clinical utility due to lack of sensitivity and specificity, and risk for delayed diagnosis and treatment.

Connective tissue disorders (CTDs), also known as collagen vascular diseases, are a heterogeneous group of diseases with a common pathogenic mechanism: autoimmunity. Precise classification of CTDs requires clinical, serologic, and pathologic correlation and may be difficult because of overlapping clinical and histologic features. The main contribution of histopathology in the diagnosis of these disorders is to confirm, rule out, or alert clinicians to the possibility of CTD as a disease category, rather than producing definitive diagnoses of specific entities. This article discusses the histopathologic spectrum of 3 common rheumatologic skin disorders: lupus erythematosus, dermatomyositis, and morphea (localized scleroderma)., (Copyright © 2017 Elsevier Inc. All rights reserved.)

Background: 5-Hydroxymethylcytosine (5-hmC) is an epigenetic marker detectable through immunohistochemistry (IHC) that has been shown to distinguish benign nevi from melanoma with high sensitivity and specificity. The purpose of the study was to explore its diagnostic utility in a subset of histologically challenging, heavily pigmented cutaneous melanocytic neoplasms., Methods: 5-hmC IHC was performed on 54 heavily pigmented melanocytic tumors. Semi-quantitative analysis of immunoreactivity was correlated with clinical, pathologic and follow-up data., Results: Benign melanocytic neoplasms (4 of 4 blue nevi with epithelioid change; 12 of 12 combined nevi; 5 of 5 deep penetrating nevi, DPN) exhibited strong 5-hmC nuclear reactivity. Eight heavily pigmented blue nevus-like melanomas and 7 of 8 pigmented epithelioid melanocytomas (PEM) showed significant 5-hmC loss. Five of 7 atypical DPN cases and 8 of 10 melanocytic tumors of uncertain malignant potential (MELTUMP) showed low to intermediate 5-hmC immunoreactivity. These differences were statistically significant (P-value <.0001)., Conclusions: Loss of 5-hmC may be helpful in differentiating benign, diagnostically challenging, heavily pigmented melanocytic tumors from those with malignant potential. The intermediate to low 5-hmC immunoreactivity in atypical DPNs, PEMs and so-called MELTUMP categories further underscores the need to consider these neoplasms as having some potential for lethal biological behavior., (© 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

Tuberous Sclerosis Complex (TSC) is an autosomal dominant tumor suppressor gene syndrome in which patients develop several types of tumors, including facial angiofibroma, subungual fibroma, Shagreen patch, angiomyolipomas, and lymphangioleiomyomatosis. It is due to inactivating mutations in TSC1 or TSC2. We sought to generate a mouse model of one or more of these tumor types by targeting deletion of the Tsc1 gene to fibroblasts using the Fsp-Cre allele. Mutant, Tsc1ccFsp-Cre+ mice survived a median of nearly a year, and developed tumors in multiple sites but did not develop angiomyolipoma or lymphangioleiomyomatosis. They did develop a prominent skin phenotype with marked thickening of the dermis with accumulation of mast cells, that was minimally responsive to systemic rapamycin therapy, and was quite different from the pathology seen in human TSC skin lesions. Recombination and loss of Tsc1 was demonstrated in skin fibroblasts in vivo and in cultured skin fibroblasts. Loss of Tsc1 in fibroblasts in mice does not lead to a model of angiomyolipoma or lymphangioleiomyomatosis., Competing Interests: The authors have declared that no competing interests exist.

Epigenetic alterations by histone/protein deacetylases (HDACs) are one of the many mechanisms that cancer cells use to alter gene expression and promote growth. HDAC inhibitors have proven to be effective in the treatment of specific malignancies, particularly in combination with other anticancer agents. We conducted a phase I trial of panobinostat in patients with unresectable stage III or IV melanoma. Patients were treated with oral panobinostat at a dose of 30 mg daily on Mondays, Wednesdays, and Fridays (Arm A). Three of the six patients on this dose experienced clinically significant thrombocytopenia requiring dose interruption. Due to this, a second treatment arm was opened and the dose was changed to 30 mg oral panobinostat three times a week every other week (Arm B). Six patients were treated on Arm A and 10 patients were enrolled to Arm B with nine patients treated. In nine patients treated on Arm B, the response rate was 0% (90% confidence interval [CI]: 0-28%) and the disease-control rate was 22% (90% CI: 4-55%). Among all 15 patients treated, the overall response rate was 0% (90% CI: 0-17%) and the disease-control rate was 27% (90% CI: 10-51%). There was a high rate of toxicity associated with treatment. Correlative studies suggest the presence of immune modifications after HDAC inhibition. Panobinostat is not active as a single agent in the treatment of melanoma. Further exploration of this agent in combination with other therapies may be warranted., (© 2016 The Authors. Cancer Medicine published by John Wiley & Sons Ltd.)

Melanoma is the deadliest form of commonly encountered skin cancer because of its rapid progression towards metastasis. Although metabolic reprogramming is tightly associated with tumour progression, the effect of metabolic regulatory circuits on metastatic processes is poorly understood. PGC1α is a transcriptional coactivator that promotes mitochondrial biogenesis, protects against oxidative stress and reprograms melanoma metabolism to influence drug sensitivity and survival. Here, we provide data indicating that PGC1α suppresses melanoma metastasis, acting through a pathway distinct from that of its bioenergetic functions. Elevated PGC1α expression inversely correlates with vertical growth in human melanoma specimens. PGC1α silencing makes poorly metastatic melanoma cells highly invasive and, conversely, PGC1α reconstitution suppresses metastasis. Within populations of melanoma cells, there is a marked heterogeneity in PGC1α levels, which predicts their inherent high or low metastatic capacity. Mechanistically, PGC1α directly increases transcription of ID2, which in turn binds to and inactivates the transcription factor TCF4. Inactive TCF4 causes downregulation of metastasis-related genes, including integrins that are known to influence invasion and metastasis. Inhibition of BRAF V600E using vemurafenib, independently of its cytostatic effects, suppresses metastasis by acting on the PGC1α-ID2-TCF4-integrin axis. Together, our findings reveal that PGC1α maintains mitochondrial energetic metabolism and suppresses metastasis through direct regulation of parallel acting transcriptional programs. Consequently, components of these circuits define new therapeutic opportunities that may help to curb melanoma metastasis., Competing Interests: The authors disclose no potential conflicts of interest. Author Information The authors declare no competing financial interests. Readers are welcome to comment on the online version of the paper.

Thromboangiitis obliterans (TAO) or Buerger's disease is a rare form of vasculitis with distinctive clinical and pathological features that carries significant morbidity, often leading to amputation, and is strongly associated with tobacco smoking. Despite its distinctive clinicopathological characteristics, the existence of TAO as an entity sui generis was challenged for many years as it languished in relative obscurity. Then, as societal attitudes towards smoking changed, TAO not only became accepted as a disease entity, it quite literally became a poster child to illustrate the ills of smoking. Herein, we examine the history of TAO to illustrate the power of societal attitudes and politics in shaping medicine.

Background: Loss of donor-mediated immune antitumor activity after allogeneic hematopoietic stem-cell transplantation (HSCT) permits relapse of hematologic cancers. We hypothesized that immune checkpoint blockade established by targeting cytotoxic T-lymphocyte-associated protein 4 with ipilimumab could restore antitumor reactivity through a graft-versus-tumor effect., Methods: We conducted a phase 1/1b multicenter, investigator-initiated study to determine the safety and efficacy of ipilimumab in patients with relapsed hematologic cancer after allogeneic HSCT. Patients received induction therapy with ipilimumab at a dose of 3 or 10 mg per kilogram of body weight every 3 weeks for a total of 4 doses, with additional doses every 12 weeks for up to 60 weeks in patients who had a clinical benefit., Results: A total of 28 patients were enrolled. Immune-related adverse events, including one death, were observed in 6 patients (21%), and graft-versus-host disease (GVHD) that precluded further administration of ipilimumab was observed in 4 patients (14%). No responses that met formal response criteria occurred in patients who received a dose of 3 mg per kilogram. Among 22 patients who received a dose of 10 mg per kilogram, 5 (23%) had a complete response, 2 (9%) had a partial response, and 6 (27%) had decreased tumor burden. Complete responses occurred in 4 patients with extramedullary acute myeloid leukemia and 1 patient with the myelodysplastic syndrome developing into acute myeloid leukemia. Four patients had a durable response for more than 1 year. Responses were associated with in situ infiltration of cytotoxic CD8+ T cells, decreased activation of regulatory T cells, and expansion of subpopulations of effector T cells in the blood., Conclusions: Our early-phase data showed that administration of ipilimumab was feasible in patients with recurrent hematologic cancers after allogeneic HSCT, although immune-mediated toxic effects and GVHD occurred. Durable responses were observed in association with several histologic subtypes of these cancers, including extramedullary acute myeloid leukemia. (Funded by the National Institutes of Health and others; ClinicalTrials.gov number, NCT01822509.).

Nevoid basal cell carcinoma syndrome, or basal cell nevus syndrome (Gorlin syndrome), is a rare autosomal dominantly inherited disorder that is characterized by development of basal cell carcinomas from a young age. Other distinguishing clinical features are seen in a majority of patients, and include keratocystic odontogenic tumors (formerly odontogenic keratocysts) as well as dyskeratotic palmar and plantar pitting. A range of skeletal and other developmental abnormalities are also often seen. The disorder is caused by defects in hedgehog signaling which result in constitutive pathway activity and tumor cell proliferation. As sporadic basal cell carcinomas also commonly harbor hedgehog pathway aberrations, therapeutic agents targeting key signaling constituents have been developed and tested against advanced sporadically occurring tumors or syndromic disease, leading in 2013 to FDA approval of the first hedgehog pathway-targeted small molecule, vismodegib. The elucidation of the molecular pathogenesis of nevoid basal cell carcinoma syndrome has resulted in further understanding of the most common human malignancy.

Dermal melanocytosis refers to a spectrum of benign melanocytic proliferations that includes Mongolian spot, nevus of Ota and nevus of Ito. These lesions most commonly occur in persons of Asian or African descent and are often present at birth or develop during childhood. Very rarely, dermal melanocytoses undergo malignant transformation. There have been only 13 reports in the literature of primary cutaneous melanoma arising in dermal melanocytoses. We report a case of a Chinese woman with melanoma arising in a congenital nevus of Ito. We performed targeted next-generation sequencing of the tumor which revealed mutations of GNAQ and BAP1, suggesting that alterations in these two genes led to malignant transformation of the nevus of Ito. We also provide a summary of reports in the literature regarding primary cutaneous melanoma arising in the context of dermal melanocytosis., (© 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

Objectives: The purpose of this study was to examine the utility of direct immunofluorescence (DIF) testing for the characteristic immunoglobulin A deposits of dermatitis herpetiformis (DH) in patients stratified into high and low clinical suspicion subgroups., Methods: We retrospectively analyzed the results of H&E and DIF testing in 77 cases of suspected DH and separated them into high and low clinical suspicion subgroups based on clinical impression at the time of biopsy., Results: The overall sensitivity and specificity of routine (H&E) histologic evaluation were 0.75 and 0.951, respectively. Although there were 13 cases of DH (of 36 total cases) in the high clinical suspicion subgroup, there were only three (of 41 total cases) in the low clinical suspicion subgroup. In the high clinical suspicion subgroup, the positive predictive value (PPV) was 0.9, and the negative predictive value (NPV) was 0.846. Alternatively, the PPV was 0.6 and the NPV was 1.0 for the low clinical suspicion subgroup. Histologic false negatives did occur, but all were in patients within the high clinical suspicion subgroup., Conclusions: It is anticipated that the NPV and PPV will vary due to differing clinical practice characteristics; however, in patients with a low clinical suspicion for DH, these data argue that it may be reasonable to first perform a biopsy for routine histologic evaluation before requesting DIF analysis., (Copyright© by the American Society for Clinical Pathology.)

Objectives: Still disease is a rare disorder characterized by seronegative arthralgias/arthritis, spiking fever, and either an evanescent salmon-colored rash or persistent papules and plaques., Methods: We describe the clinical and biopsy findings in 10 patients with the evanescent rash of Still disease., Results: Fourteen biopsy specimens were studied from seven women and three men with a mean age of 44.4 years. The skin lesions were typically erythematous macules, papules, or plaques with a median duration of 5 weeks. All patients had systemic symptoms, including fever and arthralgias. The infiltrate was predominantly lymphocytic in six biopsy specimens, approximately equal lymphocytic and neutrophilic in four biopsy specimens, and predominantly (although never exclusively) neutrophilic in four biopsy specimens. Other findings included focal vacuolar interface changes, neutrophilic eccrine hidradenitis, epidermal neutrophils, dermal mucin, and acanthosis associated with numerous upper epidermal dyskeratotic cells., Conclusions: It is important to be aware of the broad histologic spectrum that may be encountered in Still disease and to consider Still disease in the differential diagnosis of neutrophil-rich, lymphocyte-rich, and mixed inflammatory dermatoses. While the histologic findings seen in biopsy specimens of the evanescent rash are nonspecific, a distinctive variant also exists characterized by prominent epidermal apoptosis, especially involving the upper layers., (Copyright© by the American Society for Clinical Pathology.)

Complex regional pain syndrome (CRPS) is an incompletely understood disorder characterized by progressive regional pain and sensory changes, with fluctuating cutaneous edema and erythema. We describe a patient with a rarely reported severe bullous CRPS variant on the left lower extremity, which resolved immediately upon developing spinal paralysis.

Objectives: We aimed to determine if clonality on T-cell gene rearrangement studies correlated with duration of cutaneous symptoms in patients with skin disease who are being evaluated for cutaneous T-cell lymphoma (CTCL). Specifically, our goal was to determine if symptom duration could help better optimize sample selection for T-cell gene rearrangement studies., Methods: Biopsies were reviewed from patients within both general dermatology clinic and CTCL specialty clinic for clonality results in relation to disease duration., Results: We did not find an association between duration and clonality in any group., Conclusions: The yield of T-cell gene rearrangement studies is similar between shorter and longer duration of disease implying that there is not an optimal duration range in which T-cell gene rearrangement studies are more likely to give a positive result., (© 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

Objectives: We illustrate the important and troubling issue of persistent misinformation and false claims in the medical literature using a frequently cited case inaccurately believed by many to be the first case of calciphylaxis., Methods: We identified a recurring error in the medical literature in the form of numerous citations of a study from the 1890s of a 6-month-old child with idiopathic infantile arterial calcification that is purported to be the first description of a case of calciphylaxis. We performed searches to determine the frequency of this error. Google Scholar and PubMed were searched for references citing the Bryant and White article. Accuracy of the citations was determined., Results: A Google Scholar search identified 33 references that incorrectly cite the Bryant and White article as the first description of a case of calciphylaxis. Of the 100 most recent PubMed publications on calciphylaxis, we identified five studies that incorrectly attribute the Bryant and White article as the first description of calciphylaxis, which accounts for approximately 5% of the contemporary literature on this topic., Conclusions: Medical misinformation such as this is frequently perpetuated. We propose that computational resources could be better used to flag erroneous and contradicted claims to update and correct the literature., (Copyright© by the American Society for Clinical Pathology.)

Background: In 2009 the revised seventh staging system for melanoma recommended the use of mitotic count to separate stage T1a from T1b. However, careful scrutiny of cases may lead to an inadvertent selection effect, with consequent increased reporting of mitotic counts., Methods: We investigated whether there is a significant increase in mitotic counts reported since 2009 for melanomas with a Breslow thickness of 1.0 mm or less. We conducted a retrospective, case-controlled study examining invasive melanoma cases at a large academic center. Mitotic counts were compared between pathology reports before 2009 (n = 61) and after 2009 (n = 125), with a subset of slides re-examined in a blinded fashion., Results: Before the 2009 staging guidelines, 51% of cases had one or more mitosis reported compared to 38% after 2009 (p = 0.113). Blinded re-counting did not yield a significant difference when compared with the original pathology reports in either group., Conclusions: There was not a significant difference in the number of mitoses reported after the implementation of the new guidelines., (© 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

Extramammary Paget disease (EMPD) is an uncommon intraepithelial adenocarcinoma that involves body sites with apocrine glands such as the genital, perineal and perianal regions. Risk stratification and treatment planning for EMPD can be challenging. This review presents important prognostic information in EMPD to assist physicians with risk stratification of patients with EMPD. The best-understood prognostic factors are depth of invasion and involvement of extracutaneous sites. Tumours that invade into the reticular dermis or have a depth of > 1 mm are associated with poorer prognosis. Additionally, tumours spreading outside the skin into lymph nodes or other tissues are higher risk. There is an emerging understanding of the importance of tumour genetics in risk stratification, and we review the data on Ki-67, cyclin D1, Mucin 5AC and E-cadherin. There is less evidence supporting the importance of lesion site and patient age in risk stratification. This succinct review will be helpful in clinical practice and in EMPD research., (© 2015 British Association of Dermatologists.)

Malignant eccrine spiradenoma, or spiradenocarcinoma, is an exceedingly rare sweat-gland tumor, with only 102 reported cases. Low-grade carcinomas are especially rare with only a few cases reported. Because of the limited number of case reports, the biologic behavior of low-grade malignant eccrine spiradenoma is poorly understood and no evidence-based therapeutic approach is established. Here, the authors report a 29-year-old woman who presented with a history of left-sided facial lesions present since the age of 2 months. Histopathologic examination revealed multiple benign spiradenomas, several of which showed foci of low-grade malignant transformation evidenced by loss of the characteristic 2-cell population seen in the benign tumor component. Included are the clinical presentation, histopathologic description, and surgical decision making in an effort to guide recognition of this rare entity.

Background: Recent developments in genomic sequencing have advanced our understanding of the mutations underlying human malignancy. Melanoma is a prototype of an aggressive, genetically heterogeneous cancer notorious for its biologic plasticity and predilection towards developing resistance to targeted therapies. Evidence is rapidly accumulating that dysregulated epigenetic mechanisms (DNA methylation/demethylation, histone modification, non-coding RNAs) may play a central role in the pathogenesis of melanoma. Therefore, we sought to characterize the frequency and nature of mutations in epigenetic regulators in clinical, treatment-naïve, patient melanoma specimens obtained from one academic institution., Results: Targeted next-generation sequencing for 275 known and investigative cancer genes (of which 41 genes, or 14.9 %, encoded an epigenetic regulator) of 38 treatment-naïve patient melanoma samples revealed that 22.3 % (165 of 740) of all non-silent mutations affected an epigenetic regulator. The most frequently mutated genes were BRAF, MECOM, NRAS, TP53, MLL2, and CDKN2A. Of the 40 most commonly mutated genes, 12 (30.0 %) encoded epigenetic regulators, including genes encoding enzymes involved in histone modification (MECOM, MLL2, SETD2), chromatin remodeling (ARID1B, ARID2), and DNA methylation and demethylation (TET2, IDH1). Among the 38 patient melanoma samples, 35 (92.1 %) harbored at least one mutation in an epigenetic regulator. The genes with the highest number of total UVB-signature mutations encoded epigenetic regulators, including MLL2 (100 %, 16 of 16) and MECOM (82.6 %, 19 of 23). Moreover, on average, epigenetic genes harbored a significantly greater number of UVB-signature mutations per gene than non-epigenetic genes (3.7 versus 2.4, respectively; p = 0.01). Bioinformatics analysis of The Cancer Genome Atlas (TCGA) melanoma mutation dataset also revealed a frequency of mutations in the 41 epigenetic genes comparable to that found within our cohort of patient melanoma samples., Conclusions: Our study identified a high prevalence of somatic mutations in genes encoding epigenetic regulators, including those involved in DNA demethylation, histone modification, chromatin remodeling, and microRNA processing. Moreover, UVB-signature mutations were found more commonly among epigenetic genes than in non-epigenetic genes. Taken together, these findings further implicate epigenetic mechanisms, particularly those involving the chromatin-remodeling enzyme MECOM/EVI1 and histone-modifying enzyme MLL2, in the pathobiology of melanoma.

In normal melanocytes, TGF-β signaling has a cytostatic effect. However, in primary melanoma cells, TGF-β-induced cytostasis is diminished, thus allowing melanoma growth. Later, a second phase of TGF-β signaling supports melanoma EMT-like changes, invasion and metastasis. In parallel with these "present-absent-present" TGF-β signaling phases, cell surface protein EWI motif-containing protein 2 (EWI-2 or IgSF8) is "absent-present-absent" in melanocytes, primary melanoma, and metastatic melanoma, respectively, suggesting that EWI-2 may serve as a negative regulator of TGF-β signaling. Using melanoma cell lines and melanoma short-term cultures, we performed RNAi and overexpression experiments and found that EWI-2 negatively regulates TGF-β signaling and its downstream events including cytostasis (in vitro and in vivo), EMT-like changes, cell migration, CD271-dependent invasion, and lung metastasis (in vivo). When EWI-2 is present, it associates with cell surface tetraspanin proteins CD9 and CD81 - molecules not previously linked to TGF-β signaling. Indeed, when associated with EWI-2, CD9 and CD81 are sequestered and have no impact on TβR2-TβR1 association or TGF-β signaling. However, when EWI-2 is knocked down, CD9 and CD81 become available to provide critical support for TβR2-TβR1 association, thus markedly elevating TGF-β signaling. Consequently, all of those TGF-β-dependent functions specifically arising due to EWI-2 depletion are reversed by blocking or depleting cell surface tetraspanin proteins CD9 or CD81. These results provide new insights into regulation of TGF-β signaling in melanoma, uncover new roles for tetraspanins CD9 and CD81, and strongly suggest that EWI-2 could serve as a favorable prognosis indicator for melanoma patients.

Sentinel lymph node biopsies are conducted to stage patients with newly diagnosed melanomas that have histopathological attributes conferring defined levels of metastatic potential. Because benign nevic cells may also form 'deposits' in lymph nodes (nodal nevus), the pathological evaluation for metastatic melanoma within sentinel lymph nodes can be challenging. Twenty-eight sentinel lymph node biopsy cases containing either metastatic melanoma (N=18) or nodal nevi (N=10) were retrieved from the archives of the Brigham and Women's Hospital, Department of Pathology (2011-2014). In addition, two sentinel lymph node cases that were favored to represent metastatic disease but whose histopathological features were viewed as equivocal, with melanoma favored, were also included. Dual labeling for the melanocyte lineage marker, MART-1, and the epigenetic marker, 5-hydroxymethylcytosine, a functionally significant indicator that has been shown to distinguish benign nevi from melanoma, was performed on all cases using immunohistochemistry and/or direct immunofluorescence. All (18 of 18) metastatic melanoma cases showed complete loss of 5-hydroxymethylcytosine nuclear staining in MART-1-positive cells, and all (10 of 10) nodal nevus cases demonstrated 5-hydroxymethylcytosine nuclear staining in MART-1-positive cells. In addition, 5-hydroxymethylcytosine staining confirmed the favored diagnoses of metastatic melanoma in the two 'equivocal' cases. Thus, 5-hydroxymethylcytosine may be a useful adjunctive marker to distinguish between benign nodal nevi and metastatic melanoma during the evaluation of sentinel lymph node biopsies for metastatic melanoma.

Microphthalmia-associated transcription factor (MITF) acts via pigment epithelium-derived factor (PEDF), an antiangiogenic protein, to regulate retinal pigment epithelium migration. PEDF expression and/or regulation during melanoma development have not been investigated previously. Using immunohistochemistry, we determined expression of PEDF in common and dysplastic melanocytic nevi, melanoma in situ, invasive melanoma, and metastatic melanoma (n = 102). PEDF expression was consistently decreased in invasive and metastatic melanoma, compared with nevi and melanoma in situ (P < 0.0001). PEDF was lost in thicker melanomas (P = 0.003), and correlated with depth of invasion (P = 0.003) and distant metastasis (P = 0.0331), but only marginally with mitotic index, AJCC stage, nodal metastasis, or blood vascular density (0.05 < P < 0.10). Quantitative real-time PCR and microarray analyses confirmed PEDF down-regulation at the mRNA level in several melanoma lines, compared with melanocytes. MITF positively correlated with PEDF expression in invasive melanomas (P = 0.0003). Searching for PEDF regulatory mechanisms revealed two occupied conserved E-boxes (DNA recognition elements) in the first intron of the human and mouse PEDF promoter regions, confirmed by binding assays. Dominant-negative and siRNA approaches in vivo demonstrated direct transcriptional influence of MITF on PEDF, establishing the PEDF gene (SERPINF1) as a MITF target in melanocytes and melanoma cells. These findings suggest that loss of PEDF expression promotes early invasive melanoma growth., (Copyright © 2015 American Society for Investigative Pathology. Published by Elsevier Inc. All rights reserved.)

Objectives: It is well recognized that biases exist in medical decision making. We sought evidence for such bias in diagnostic testing., Methods: We investigated whether a cytotechnologist's Papanicolaou (Pap) test interpretation of a squamous cell abnormality influenced the likelihood of making the same interpretation again that day using analysis based on the β distribution., Results: For squamous intraepithelial lesion (SIL) interpretations, significant deviation away from the mean daily diagnostic rate was seen within all three cytotechnologists and, for atypical squamous cells of undetermined significance interpretations, within two of three., Conclusions: Cytotechnologists are not influenced by an expected number of abnormal Pap cases per day since this would result in deviation toward the mean daily rate of diagnosis. Possible explanations for the unanticipated clustering of SIL interpretations include clinical clustering effects or, alternatively, the influence a SIL interpretation might have on lowering the threshold for this interpretation again in subsequent specimens on the same day. The analysis presented here could serve as a model to detect bias in other aspects of medical decision making., (Copyright© by the American Society for Clinical Pathology.)

Scleromyxedema is a generalized and progressive fibromucinous disorder associated with substantial cutaneous and systemic morbidity. The diagnosis is often challenging, as is management. We present here a patient with scleromyxedema with atypical, granuloma annulare-like histology, which contributed to delayed diagnosis and management, including a delayed workup for multiple myeloma. Ultimately, the patient did well with appropriate therapy, but his presentation illustrates the importance of more widespread familiarity among dermatologists and dermatopathologists with this variant of scleromyxedema.

Objectives: The purpose of this study was to examine the utility of immunofluorescence (IF) testing in patients with leukocytoclastic vasculitis (LCV), particularly with regard to usefulness in the diagnosis of Henoch-Schönlein purpura (HSP)., Methods: We retrospectively analyzed the results of IF testing in 96 patients with LCV and compared results with clinical criteria and clinical impression at the time of biopsy by review of the medical record., Results: Sensitivity and specificity of vascular immunoglobulin A (IgA) for the diagnosis of HSP were 0.86 and 0.84, respectively. Positive predictive value was 0.48 and negative predictive value was 0.97. Of the 53 patients with LCV who did not meet clinical criteria for HSP and carried a low clinical suspicion for the disease at the time of biopsy, seven had moderate to strong staining for vascular IgA. Only one of these patients was determined to have HSP., Conclusions: Our data confirm that vascular IgA is nonspecific and also demonstrate that the utility of IF studies for vasculitis is influenced by the clinical presentation and the clinician's level of suspicion for HSP. Our data show that the clinical features and the overall clinical impression are helpful in selecting which patients are most likely to benefit from IF testing., (Copyright© by the American Society for Clinical Pathology.)

Neutrophilic dermatoses are a rare manifestation of systemic lupus erythematosus (SLE). In recent years, a growing body of literature describes a pathologic spectrum of neutrophilic infiltrates that may be seen in lupus patients. It is particularly important to recognize that neutrophilic dermatoses can be the initial manifestation of SLE in a third of patients. We were able to identify 47 patients with SLE associated with neutrophilic tissue reactions. In this review, we describe the histologic and clinical features of these cases in the hope that increased awareness of this unusual manifestation of SLE will generate prompt diagnosis and improved patient care.

This series of 113 sequential biopsies of full facial transplants provides findings of potential translational significance as well as biological insights that could prompt reexamination of conventional paradigms of effector pathways in skin allograft rejection. Serial biopsies before, during, and after rejection episodes were evaluated for clinicopathological assessment that in selected cases included specific biomarkers for donor-versus-recipient T cells. Histologic evidence of rejection included lymphocyte-associated injury to epidermal rete ridges, follicular infundibula, and dermal microvessels. Surprisingly, during active rejection, immune cells spatially associated with target cell injury consisted abundantly or predominantly of lymphocytes of donor origin with an immunophenotype typical of the resident memory T-cell subset. Current dogma assumes that skin allograft rejection is mediated by recipient T cells that attack epidermal targets, and the association of donor T cells with sites of target cell injury raises questions regarding the potential complexity of immune cell interactions in the rejection process. A more histopathologically refined and immune-based biomarker approach to assessment of rejection of facial transplants is now indicated.

Context: Skin neoplasms include the most common malignancies affecting humans. Many show an ultraviolet (UV)-induced pathogenesis and often affect the head and neck region., Objective: To review literature on cutaneous neoplasms that show a predilection for the head and neck region and that are associated with molecular alterations., Data Sources: Literature review., Conclusions: Common nonmelanoma skin cancers, such as basal and squamous cell carcinomas, show a UV-induced pathogenesis. Basal cell carcinomas are characterized by molecular alterations of the Hedgehog pathway, affecting patched and smoothened genes. While squamous cell carcinomas show UV-induced mutations in several genes, driver mutations are only beginning to be identified. In addition, certain adnexal neoplasms also predominantly affect the head and neck region and show interesting, recently discovered molecular abnormalities, or are associated with hereditary conditions whose molecular genetic pathogenesis is well understood. Furthermore, recent advances have led to an increased understanding of the molecular pathogenesis of melanoma. Certain melanoma subtypes, such as lentigo maligna melanoma and desmoplastic melanoma, which are more often seen on the chronically sun-damaged skin of the head and neck, show differences in their molecular signature when compared to the other more common subtypes, such as superficial spreading melanoma, which are more prone to occur at sites with acute intermittent sun damage. In summary, molecular alterations in cutaneous neoplasms of the head and neck are often related to UV exposure. Their molecular footprint often reflects the histologic tumor type, and familiarity with these changes will be increasingly necessary for diagnostic and therapeutic considerations.

Objectives: Ancillary molecular testing on tissue is available for mycobacterial disease; however, judicious use of highly sensitive tests, such as polymerase chain reaction (PCR) and sequencing, should be guided by histologic parameters. We sought to investigate the utility of performing acid-fast stains (AFS) on skin biopsy specimens with granulomatous inflammation without an otherwise obvious histologic or clinical explanation., Methods: Our retrospective review identified 31 patients with biopsy specimens showing granulomatous inflammation that had simultaneous AFS and mycobacterial culture or PCR performed., Results: Biopsy specimens from eight (25.8%) patients had AFS interpreted as positive or suspicious for acid-fast bacilli. Eight had positive cultures and one had positive PCR. One biopsy specimen with AFS that showed occasional acid-fast structures that were interpreted as "suspicious" for mycobacteria was associated with a negative culture and negative PCR. Three (9.7%) biopsy specimens with negative AFS had positive cultures, and 19 (61.3%) biopsy specimens with negative AFS also had negative culture results. In our biopsy specimens, sensitivity of AFS was 72.7% and specificity was 95.0%. Positive predictive value of AFS was 88.9%, and negative predictive value was 86.4%., Conclusions: AFS has good sensitivity and excellent specificity and should be performed on all unexplained granulomatous tissue reactions of skin in conjunction with mycobacterial culture.

Neutrophilic dermatoses are an uncommon manifestation of lupus. We describe the clinical and histopathologic features of 14 patients with systemic lupus erythematosus (SLE) and neutrophilic dermatoses, 2 of whom had no prior history of SLE. Thirteen patients were female, ranging in age from 27 to 62 years (mean age, 42.8 years). One patient was a 20-year-old man. Most lesions were described as erythematous papules and plaques and showed annular morphology in 6 patients and a photodistribution in 2 patients. Histopathologic examination in all cases showed an interstitial neutrophilic infiltrate with leukocytoclasis that ranged from sparse in 5 cases and moderate to dense in 9 cases. With one exception, those cases with moderate to dense infiltrates resembled Sweet's syndrome at scanning magnification. Two cases resembled bullous SLE, and 1 case showed overlapping features of bullous SLE and Sweet's syndrome. Interface changes were seen in 8 patients, which were subtle and vacuolar in 7. One case was associated with a florid interface tissue reaction. Dermal mucin was seen in 4 cases and was a prominent feature in only one of these. One case showed a minute discrete focus resembling palisaded neutrophilic and granulomatous dermatitis. It is important to consider SLE-associated neutrophilic dermatosis in the differential diagnosis of neutrophilic tissue reactions particularly because some patients will have no prior history of lupus. It is also important to be aware of the broad histologic spectrum that may be encountered in SLE-associated neutrophilic dermatosis, ranging from subtle paucicellular lesions to florid Sweet's-like lesions associated with a dense neutrophilic infiltrate., (Copyright © 2014 Elsevier Inc. All rights reserved.)

The current rapid rate of species extinction and loss of biodiversity occurring throughout the world has the potential to exact far-reaching adverse impacts on human health in many ways, including increasing the risk of infectious disease transmission. Here, we use Lyme disease as a model to illustrate how loss of biodiversity in the community of vertebrates may lead to increased transmission of zoonotic pathogens in humans. We also illustrate how preserving biodiversity has the potential to reduce the prevalence of human infectious disease more generally.