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How targeted therapies and immunotherapies shape tumors, and thereby influence subsequent therapeutic responses, is poorly understood. In the present study, we show, in melanoma patients and mouse models, that when tumors relapse after targeted therapy with MAPK pathway inhibitors, they are cross-resistant to immunotherapies, despite the different modes of action of these therapies. We find that cross-resistance is mediated by a cancer cell–instructed, immunosuppressive tumor microenvironment that lacks functional CD103+ dendritic cells, precluding an effective T cell response. Restoring the numbers and functionality of CD103+ dendritic cells can re-sensitize cross-resistant tumors to immunotherapy. Cross-resistance does not arise from selective pressure of an immune response during evolution of resistance, but from the MAPK pathway, which not only is reactivated, but also exhibits an increased transcriptional output that drives immune evasion. Our work provides mechanistic evidence for cross-resistance between two unrelated therapies, and a scientific rationale for treating patients with immunotherapy before they acquire resistance to targeted therapy. Obenauf and colleagues report that acquired resistance to BRAF and MEK inhibitors in melanoma confers cross-resistance to immune checkpoint blockade by fostering a cancer cell–instructed, immune-evasive tumor microenvironment.

Tumor associated inflammation predicts response to immune checkpoint blockade in human melanoma. Current theories on regulation of inflammation center on anti-tumor T cell responses. Here we show that tumor associated B cells are vital to melanoma associated inflammation. Human B cells express pro- and anti-inflammatory factors and differentiate into plasmablast-like cells when exposed to autologous melanoma secretomes in vitro. This plasmablast-like phenotype can be reconciled in human melanomas where plasmablast-like cells also express T cell-recruiting chemokines CCL3, CCL4, CCL5. Depletion of B cells in melanoma patients by anti-CD20 immunotherapy decreases tumor associated inflammation and CD8+ T cell numbers. Plasmablast-like cells also increase PD-1+ T cell activation through anti-PD-1 blockade in vitro and their frequency in pretherapy melanomas predicts response and survival to immune checkpoint blockade. Tumor associated B cells therefore orchestrate and sustain melanoma inflammation and may represent a predictor for survival and response to immune checkpoint blockade therapy., The regulation of tumor inflammation is incompletely understood and the role of B cells is unclear. Here, the authors show that a specific subtype of B cells is induced in melanoma and required to recruit T lymphocytes and elicit inflammation.

Background: Recent cost-utility analysis (CUA) models for onasemnogene abeparvovec (Zolgensma®, formerly AVXS-101) in spinal muscular atrophy type 1 (SMA1) differ on key assumptions and results. Objective: To compare the manufacturer’s proprietary CUA model to the model published by the Institute for Clinical and Economic Review (ICER), and to update the manufacturer’s model with long-term follow-up data and some key ICER assumptions. Study design: We updated a recent CUA evaluating value for money in cost per incremental Quality-adjusted Life Year (QALY) of onasemnogene abeparvovec versus nusinersen (Spinraza®) or best supportive care (BSC) in symptomatic SMA1 patients, and compared it to the ICER model. Setting/Perspective: USA/Commercial payer Participants: Children aged

Merkel cell carcinoma (MCC) is a highly aggressive, neuroendocrine skin cancer that lacks actionable mutations, which could be utilized for targeted therapies. Epigenetic regulators governing cell identity may represent unexplored therapeutic entry points. Here, we targeted epigenetic regulators in a pharmacological screen and discovered that the lysine‐specific histone demethylase 1A (LSD1/KDM1A) is required for MCC growth in vitro and in vivo. We show that LSD1 inhibition in MCC disrupts the LSD1‐CoREST complex leading to displacement and degradation of HMG20B (BRAF35), a poorly characterized complex member that is essential for MCC proliferation. Inhibition of LSD1 causes derepression of transcriptional master regulators of the neuronal lineage, activates a gene expression signature resembling normal Merkel cells, and induces cell cycle arrest and cell death. Our study unveils the importance of LSD1 for maintaining cellular plasticity and proliferation in MCC. There is also growing evidence that cancer cells exploit cellular plasticity and dedifferentiation programs to evade destruction by the immune system. The combination of LSD1 inhibitors with checkpoint inhibitors may thus represent a promising treatment strategy for MCC patients., This study identifies that the integrity of the LSD1‐CoREST complex is essential for Merkel cell carcinoma (MCC) proliferation and maintaining cell identity. LSD1 inhibition causes derepression of transcriptional regulators of the neuronal lineage and is a novel entry point for targeted therapies in MCC.

Background Chilblains ('COVID toes') are being seen with increasing frequency in children and young adults during the COVID-19 pandemic. Detailed histopathological descriptions of COVID-19 chilblains have not been reported, and causality of SARS-CoV-2 has not yet been established. Objectives To describe the histopathological features of COVID-19 chilblains and to explore the presence of SARS-CoV-2 in the tissue. Methods We examined skin biopsies from seven paediatric patients presenting with chilblains during the COVID-19 pandemic. Immunohistochemistry for SARS-CoV-2 was performed in all cases and electron microscopy in one. Results Histopathology showed variable degrees of lymphocytic vasculitis ranging from endothelial swelling and endotheliitis to fibrinoid necrosis and thrombosis. Purpura, superficial and deep perivascular lymphocytic inflammation with perieccrine accentuation, oedema, and mild vacuolar interface damage were also seen. SARS-CoV-2 immunohistochemistry was positive in endothelial cells and epithelial cells of eccrine glands. Coronavirus particles were found in the cytoplasm of endothelial cells on electron microscopy. Conclusions Although the clinical and histopathological features were similar to other forms of chilblains, the presence of viral particles in the endothelium and the histological evidence of vascular damage support a causal relation of the lesions with SARS-CoV-2. Endothelial damage induced by the virus could be the key mechanism in the pathogenesis of COVID-19 chilblains and perhaps also in a group of patients severely affected by COVID-19 presenting with features of microangiopathic damage. What is already known about this topic? Despite the high number of cases of chilblains seen during the COVID-19 pandemic, a definite causative role for SARS-CoV-2 has not yet been proven. Different pathogenetic hypotheses have been proposed, including coagulation anomalies, interferon release and external factors. What does this study add? The demonstration of SARS-CoV-2 in endothelial cells of skin biopsies by immunohistochemistry and electron microscopy confirms that these lesions are part of the spectrum of COVID-19. Virus-induced vascular damage and secondary ischaemia could explain the pathophysiology of COVID-19 chilblains. Our findings support the hypothesis that widespread endothelial infection by SARS-CoV-2 could have a pathogenetic role in the severe forms of COVID-19. Linked Comment: Wetter. Br J Dermatol 2020; 183:611.

Merkel cell carcinoma (MCC) is a highly aggressive, neuroendocrine skin cancer that is either associated with the clonal integration of the Merkel cell polyomavirus or with chronic sun exposure1,2. Immunotherapy is initially effective in many patients with metastatic MCC, but the response is rarely durable3,4. MCC lacks actionable mutations that could be utilized for targeted therapies, but epigenetic regulators, which govern cell fate, provide unexplored therapeutic entry points. Here, we performed a pharmacological screen in MCC cells, targeting epigenetic regulators. We discovered that the lysine-specific histone demethylase 1A (LSD1/KDM1A) is required for MCC growth in vitro and in vivo. HMG20B (BRAF35), a poorly characterized subunit of the LSD1-CoREST complex, is also essential for MCC proliferation. LSD1 inhibition in MCC disrupts the LSD1-CoREST complex, directly induces the expression of key regulators of the neuronal lineage and of members of the TGFβ pathway, and activates a gene expression signature corresponding to normal Merkel cells. Our results provide a rationale for evaluating LSD1 inhibitors, which are currently being tested in patients with leukemia and solid tumors, in MCC.

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.

Merkel cell carcinoma is a primary cutaneous neuroendocrine carcinoma, which once metastatic is difficult to treat. Recent mutation analyses of Merkel cell carcinoma revealed a low number of mutations in Merkel cell polyomavirus-associated tumors, and a high number of mutations in virus-negative combined squamous cell and neuroendocrine carcinomas of chronically sun-damaged skin. We speculated that the paucity of mutations in virus-positive Merkel cell carcinoma may reflect a pathomechanism that depends on derangements of chromatin without alterations in the DNA sequence (epigenetic dysregulation). One central epigenetic regulator is the Polycomb repressive complex 2 (PRC2), which silences genomic regions by trimethylating (me3) lysine (K) 27 of histone H3, and thereby establishes the histone mark H3K27me3. Recent experimental research data demonstrated that PRC2 loss in mice skin results in the formation of Merkel cells. Prompted by these findings, we explored a possible contribution of PRC2 loss in human Merkel cell carcinoma. We examined the immunohistochemical expression of H3K27me3 in 35 Merkel cell carcinomas with pure histological features (22 primary and 13 metastatic lesions) and in 5 combined squamous and neuroendocrine carcinomas of the skin. We found a strong reduction of H3K27me3 staining in tumors with pure histologic features and virus-positive Merkel cell carcinomas. Combined neuroendocrine carcinomas had no or only minimal loss of H3K27me3 labeling. Our findings suggest that a PRC2-mediated epigenetic deregulation may play a role in the pathogenesis of virus-positive Merkel cell carcinomas and in tumors with pure histologic features.

Specific history-taking, drawing a family tree and thorough clinical examination are explained in detail. Standards and calibration in audiometry are presented. Pure-tone audiometry (PTA) and principles of masking, loudness tests and dead-region testing are outlined. Different test methods of behavioural measurements in children are provided.

The prognosis of childhood hearing impairment depends upon the type of hearing disorder diagnosed, its severity and time of onset, the time points at which the hearing impairment was detected and treatment begun, the nature and quality of the treatment and of professional and family support and the presence of associated disorders.

A number of common driver mutations have been identified in melanoma, but other genetic or epigenetic aberrations are also likely to play a role in the pathogenesis of melanoma and present potential therapeutic targets. Translocations of the anaplastic lymphoma kinase (ALK), for example, have been reported in spitzoid melanocytic neoplasms leading to kinase-fusion proteins that result in immunohistochemically detectable ALK expression. In this study, we sought to determine whether ALK was also expressed in non-spitzoid primary and metastatic cutaneous melanomas. ALK immunohistochemistry (IHC) was performed on 603 melanomas (303 primary and 300 metastatic tumors) from 600 patients. ALK IHC expression was identified in 7 primary and 9 metastatic tumors. In 5 of 7 primary tumors and in 6 of 9 metastatic lesions, the majority of tumor cells were immunoreactive for ALK. In the other two primary and three metastatic lesions, positive staining was identified in less than half of the tumor cells. ALK-positivity was found in the presence or absence of BRAF or NRAS mutations. In contrast to prior observations with ALK-positive Spitz tumors, none of the ALK-positive melanomas harbored a translocation. Instead, the ALK-positive melanomas predominantly expressed the recently described ALK isoform, ALKATI, which lacks the extracellular and transmembrane domains of wild-type ALK, consists primarily of the intracellular tyrosine kinase domain, and originates from an alternative transcriptional initiation (ATI) site within the ALK gene. The findings are clinically relevant as patients with metastatic melanoma who have ALK expression may potentially benefit from treatment with ALK kinase inhibitors.

Objectives It is essential to monitor hearing status in children not only as a mandatory requirement during universal newborn hearing screening (UNHS), but also later during preschool and school-age development. The present study considers the appropriateness of the Frequency-specific Animal Sound Test (FAST4) for use in children between the ages of 2.5 and 10 years; the comparability of hearing thresholds determined using FAST4 and those measured by pure tone audiometry (PTA); and the clinical and diagnostic utility of FAST4 in a variety of pediatric settings. Methods 322 children aged 2.6–14.1 years and 41 adults were tested with FAST4. Four animal sounds were presented via headphones and a hearing threshold was determined for the high and low frequency range. In addition, the hearing threshold of each child was measured by PTA. Results Results were analyzed from 156 normal-hearing and hearing-impaired children, mostly above the age of 4 years. In general, FAST4 yielded hearing levels comparable with those from PTA in children and in adults. FAST4 frequently had to be halted prematurely in children under 4 years old. Conclusions FAST4 is a strong candidate for use as an instrument for preschool hearing screening and offers several advantages over other hearing tests. FAST4 permits simple, swift and efficient determination of the hearing threshold and the test can be administered by staff without specialist training. A number of improvements have already been integrated into the successor model known as mFAST.

Histopathological evaluation of melanocytic tumours usually allows reliable distinction of benign melanocytic naevi from melanoma. More difficult is the histopathological classification of Spitz tumours, a heterogeneous group of tumours composed of large epithelioid or spindle-shaped melanocytes. Spitz tumours are biologically distinct from conventional melanocytic naevi and melanoma, as exemplified by their distinct patterns of genetic aberrations. Whereas common acquired naevi and melanoma often harbour BRAF mutations, NRAS mutations, or inactivation of NF1, Spitz tumours show HRAS mutations, inactivation of BAP1 (often combined with BRAF mutations), or genomic rearrangements involving the kinases ALK, ROS1, NTRK1, BRAF, RET, and MET. In Spitz naevi, which lack significant histological atypia, all of these mitogenic driver aberrations trigger rapid cell proliferation, but after an initial growth phase, various tumour suppressive mechanisms stably block further growth. In some tumours, additional genomic aberrations may abrogate various tumour suppressive mechanisms, such as cell-cycle arrest, telomere shortening, or DNA damage response. The melanocytes then start to grow in a less organised fashion and may spread to regional lymph nodes, and are termed atypical Spitz tumours. Upon acquisition of even more aberrations, which often activate additional oncogenic pathways or alter cell differentiation, the neoplastic cells become entirely malignant and may colonise and take over distant organs (spitzoid melanoma). The sequential acquisition of genomic aberrations suggests that Spitz tumours represent a continuous biological spectrum, rather than a dichotomy of benign versus malignant, and that tumours with ambiguous histological features (atypical Spitz tumours) might be best classified as low-grade melanocytic tumours. The number of genetic aberrations usually correlates with the degree of histological atypia and explains why existing ancillary genetic techniques, such as array comparative genomic hybridisation (CGH) or fluorescence in situ hybridisation (FISH), are usually capable of accurately classifying histologically benign and malignant Spitz tumours, but are not very helpful in the diagnosis of ambiguous melanocytic lesions. Nevertheless, we expect that progress in our understanding of tumour progression will refine the classification of spitzoid melanocytic tumours in the near future. By integrating clinical, pathological, and genetic criteria, distinct tumour subsets will be defined within the heterogeneous group of Spitz tumours, which will eventually lead to improvements in diagnosis, prognosis and therapy.

Purpose: The aim of this study was to use massively parallel DNA sequencing to identify GNAQ/11, BAP1 and SF3B1 mutations in ophthalmic melanocytoma. Procedures: Six ophthalmic melanocytoma specimens (1 iridociliary and 5 optic nerve) were profiled for genomic alterations in GNAQ/11, BAP1 and SF3B1 using a custom deep sequencing assay. This assay uses solution phase hybridization-based exon capture and deep-coverage massively parallel DNA sequencing to interrogate all protein-coding exons and select introns. Results: The only iridociliary melanocytoma showed a mutation in GNAQ but not in BAP1. Of the 2 optic-nerve melanocytomas that developed into melanoma, one had a GNAQ mutation and both a BAP1 mutation and monosomy 3. The remaining 3 optic-nerve melanocytomas did not reveal mutations in GNAQ/11 or BAP1. SF3B1 mutations were not detected in any specimen. Conclusions: The presence of GNAQ mutation in some iridociliary and optic-nerve melanocytomas suggests a possible relationship between ophthalmic melanocytoma and other ophthalmic melanocytic neoplasms. BAP1 mutation may accompany the transformation of ophthalmic melanocytoma to melanoma.

The emergence of resistant cell clones to targeted therapies poses a significant issue in the treatment of metastatic melanoma. While these founding clones are often extremely rare in a starting population, their isolation and characterization holds unique potential for understanding disease processes, uncovering novel biomarkers and developing therapeutic concepts. The functional characterization of such founder clones and comprehensive comparisons to their post-selection counterparts requires live cells. To achieve this, we developed a novel lineage tracing tool termed CaTCH (CRISPRa tracing of clones in heterogeneous cell populations). CaTCH combines precise mapping of the lineage history of millions of cells with the ability to isolate any given clone alive from a complex population based on genetic barcodes. CaTCH thereby enables the retrospective isolation and analysis of founding clones from heterogeneous cell populations prior to evolutionary selection. In first applications, we use CaTCH to provide insights into the development of resistance to targeted cancer therapies. We demonstrate that CaTCH can be used to trace and isolate a single pre-existing therapy-resistant clone from a complex cancer cell population in vitro. Furthermore, we validate the utility of CaTCH for applications in vivo by investigating the origins of resistance to clinically relevant RAF/MEK inhibition in an immunocompetent melanoma mouse model. Here we find that most clones have the capacity to acquire resistance to combined RAF/MEK inhibitor therapy, indicating that resistance to this clinically relevant regimen is a universally achievable state in this model. We envision that CaTCH will address fundamental questions in basic and translational research (e.g., how cell identity states and trajectories are determined in therapy resistance, metastasis formation, tissue development and somatic cell re-programming), potentially revealing new vulnerabilities that can serve as targets for therapies. Citation Format: Christian Umkehrer, Felix Holstein, Laura Formenti, Julian Jude, Kimon Froussios, Tobias Neumann, Shona M. Cronin, Lisa Haas, Jesse Lipp, Thomas R. Burkard, Michaela Fellner, Thomas Wiesner, Johannes Zuber, Anna C. Obenauf. CaTCH - A barcode-guided CRISPRa-inducible reporter to isolate clones from heterogeneous populations [abstract]. In: Proceedings of the AACR Virtual Special Conference on Tumor Heterogeneity: From Single Cells to Clinical Impact; 2020 Sep 17-18. Philadelphia (PA): AACR; Cancer Res 2020;80(21 Suppl):Abstract nr PO-132.

SUMMARY Uveal melanoma (UM) is characterized by mutually exclusive activating mutations in GNAQ, GNA11, CYSLTR2, and PLCB4, four genes in a linear pathway to activation of PLCβ in almost all tumors and loss of BAP1 in the aggressive subset. We generated mice with melanocyte-specific expression of GNA11Q209L with and without homozygous Bap1 loss. The GNA11Q209L mice recapitulated human Gq-associated melanomas, and they developed pigmented neoplastic lesions from melanocytes of the skin and non-cutaneous organs, including the eye and leptomeninges, as well as at atypical sites, including the lymph nodes and lungs. The addition of Bap1 loss increased tumor proliferation and cutaneous melanoma size. Integrative transcriptome analysis of human and murine melanomas identified RasGRP3 to be specifically expressed in GNAQ/GNA11-driven melanomas. In human UM cell lines and murine models, RasGRP3 is specifically required for GNAQ/GNA11-driven Ras activation and tumorigenesis. This implicates RasGRP3 as a critical node and a potential target in UM., In Brief Moore et al. generate a preclinical mouse model of melanoma that recapitulates features of aggressive uveal melanoma. By comparing murine and human melanomas, they identify a dependency on RasGRP3 in uveal melanoma.

Atypical fibroxanthomas and pleomorphic dermal sarcomas are tumors arising in sun-damaged skin of elderly patients. They have differing prognoses and are currently distinguished using histological criteria, such as invasion of deeper tissue structures, necrosis and lymphovascular or perineural invasion. To investigate the as-yet poorly understood genetics of these tumors, 41 atypical fibroxanthomas and 40 pleomorphic dermal sarcomas were subjected to targeted next-generation sequencing approaches as well as DNA copy number analysis by comparative genomic hybridization. In an analysis of the entire coding region of 341 oncogenes and tumor suppressor genes in 13 atypical fibroxanthomas using an established hybridization-based next-generation sequencing approach, we found that these tumors harbor a large number of mutations. Gene alterations were identified in more than half of the analyzed samples in FAT1, NOTCH1/2, CDKN2A, TP53, and the TERT promoter. The presence of these alterations was verified in 26 atypical fibroxanthoma and 35 pleomorphic dermal sarcoma samples by targeted amplicon-based next-generation sequencing. Similar mutation profiles in FAT1, NOTCH1/2, CDKN2A, TP53, and the TERT promoter were identified in both atypical fibroxanthoma and pleomorphic dermal sarcoma. Activating RAS mutations (G12 and G13) identified in 3 pleomorphic dermal sarcoma were not found in atypical fibroxanthoma. Comprehensive DNA copy number analysis demonstrated a wide array of different copy number gains and losses, with similar profiles in atypical fibroxanthoma and pleomorphic dermal sarcoma. In summary, atypical fibroxanthoma and pleomorphic dermal sarcoma are highly mutated tumors with recurrent mutations in FAT1, NOTCH1/2, CDKN2A, TP53, and the TERT promoter, and a range of DNA copy number alterations. These findings suggest that atypical fibroxanthomas and pleomorphic dermal sarcomas are genetically related, potentially representing two ends of a common tumor spectrum and distinguishing these entities is at present still best performed using histological criteria.Modern Pathology advance online publication, 3 November 2017; doi:10.1038/modpathol.2017.146.

Angiosarcomas are rare malignant mesenchymal tumors of endothelial differentiation. The clinical behavior is usually aggressive and the prognosis for patients with advanced disease is poor with no effective therapies. The genetic bases of these tumors have been partially revealed in recent studies reporting genetic alterations such as amplifications of MYC (primarily in radiation-associated angiosarcomas), inactivating mutations in PTPRB and R707Q hotspot mutations of PLCG1. Here, we performed a comprehensive genomic analysis of 34 angiosarcomas using a clinically-approved, hybridization-based targeted next-generation sequencing assay for 341 well-established oncogenes and tumor suppressor genes. Over half of the angiosarcomas (n = 18, 53%) harbored genetic alterations affecting the MAPK pathway, involving mutations in KRAS, HRAS, NRAS, BRAF, MAPK1 and NF1, or amplifications in MAPK1/CRKL, CRAF or BRAF. The most frequently detected genetic aberrations were mutations in TP53 in 12 tumors (35%) and losses of CDKN2A in 9 tumors (26%). MYC amplifications were generally mutually exclusive of TP53 alterations and CDKN2A loss and were identified in 8 tumors (24%), most of which (n = 7, 88%) arose post-irradiation. Previously reported mutations in PTPRB (n = 10, 29%) and one (3%) PLCG1 R707Q mutation were also identified. Our results demonstrate that angiosarcomas are a genetically heterogeneous group of tumors, harboring a wide range of genetic alterations. The high frequency of genetic events affecting the MAPK pathway suggests that targeted therapies inhibiting MAPK signaling may be promising therapeutic avenues in patients with advanced angiosarcomas. OA gold

Desmoplastic melanoma is an uncommon variant of melanoma with sarcomatous histology, distinct clinical behavior and unknown pathogenesis. We performed low-coverage genome and high-coverage exome sequencing of 20 desmoplastic melanomas, followed by targeted sequencing of 293 genes in a validation cohort of 42 cases. A high mutation burden (median of 62 mutations/Mb) ranked desmoplastic melanoma among the most highly mutated cancers. Mutation patterns strongly implicate ultraviolet radiation as the dominant mutagen, indicating a superficially located cell of origin. Newly identified alterations included recurrent promoter mutations of NFKBIE, encoding NF-κB inhibitor ɛ (IκBɛ), in 14.5% of samples. Common oncogenic mutations in melanomas, in particular in BRAF (encoding p.Val600Glu) and NRAS (encoding p.Gln61Lys or p.Gln61Arg), were absent. Instead, other genetic alterations known to activate the MAPK and PI3K signaling cascades were identified in 73% of samples, affecting NF1, CBL, ERBB2, MAP2K1, MAP3K1, BRAF, EGFR, PTPN11, MET, RAC1, SOS2, NRAS and PIK3CA, some of which are candidates for targeted therapies.

Hintergrund Spitzoide melanozytare Neoplasien (Spitz-Navi, atypische Spitz-Tumoren, spitzoide Melanome) sind eine klinisch, histopathologisch und genetisch heterogene Gruppe melanozytarer Hauttumoren.

Blue nevi are common melanocytic tumors arising in the dermal layer of the skin. Similar to uveal melanomas, blue nevi frequently harbor GNAQ and GNA11 mutations. Recently, recurrent CYSLTR2 and PLCB4 mutations were identified in uveal melanomas not harboring GNAQ or GNA11 mutations. All four genes (GNAQ, GNA11, CYSLTR2, and PLCB4) code for proteins involved in the same signaling pathway, which is activated by mutations in these genes. Given the related functional consequences of these mutations and the known genetic similarities between uveal melanoma and blue nevi, we analyzed a cohort of blue nevi to investigate whether CYSLTR2 and PLCB4 mutations occur in tumors lacking GNAQ or GNA11 mutations (as in uveal melanoma). A targeted next-generation sequencing assay covering known activating mutations in GNAQ, GNA11, CYSLTR2, PLCB4, KIT, NRAS, and BRAF was applied to 103 blue nevi. As previously reported, most blue nevi were found to harbor activating mutations in GNAQ (59%, n = 61), followed by less frequent mutations in GNA11 (16%, n = 17). Additionally, one BRAF (1%) and three NRAS (3%) mutations were detected. In three tumors (3%) harboring none of the aforementioned gene alterations, CYSLTR2 mutations were identified. All three CYSLTR2 mutations were the same c.386T > A, L129Q mutation previously identified in uveal melanoma that has been shown to lead to increased receptor activation and signaling. In summary, our study identifies CYSLTR2 L129Q alterations as a previously unrecognized activating mutation in blue nevi, occuring in a mutually exclusive fashion with known GNAQ and GNA11 mutations. Similar to GNAQ and GNA11 mutations, CYSLTR2 mutations, when present, are likely defining pathogenetic events in blue nevi.

Malignant peripheral nerve sheath tumors (MPNSTs) represent a group of highly aggressive soft-tissue sarcomas that may occur sporadically, in association with neurofibromatosis type I (NF1 associated) or after radiotherapy. Using comprehensive genomic approaches, we identified loss-of-function somatic alterations of the Polycomb repressive complex 2 (PRC2) components (EED or SUZ12) in 92% of sporadic, 70% of NF1-associated and 90% of radiotherapy-associated MPNSTs. MPNSTs with PRC2 loss showed complete loss of trimethylation at lysine 27 of histone H3 (H3K27me3) and aberrant transcriptional activation of multiple PRC2-repressed homeobox master regulators and their regulated developmental pathways. Introduction of the lost PRC2 component in a PRC2-deficient MPNST cell line restored H3K27me3 levels and decreased cell growth. Additionally, we identified frequent somatic alterations of CDKN2A (81% of all MPNSTs) and NF1 (72% of non-NF1-associated MPNSTs), both of which significantly co-occur with PRC2 alterations. The highly recurrent and specific inactivation of PRC2 components, NF1 and CDKN2A highlights their critical and potentially cooperative roles in MPNST pathogenesis.

Most malignant peripheral nerve sheath tumors (MPNSTs) exhibit combined inactivation of NF1, CDKN2A, and polycomb repressive complex 2 component genes (Embryonic Ectoderm Development [EED] and Suppressor of Zeste 12 [SUZ12]). Mutations in EED and SUZ12 induce loss of trimethylation at lysine 27 of histone 3 (H3K27me3), with subsequent aberrant transcriptional activation of polycomb repressive complex 2–repressed homeobox master regulators. These findings prompted us to investigate the performance of an anti-H3K27me3 monoclonal antibody clone C36B11 as an immunohistochemical marker for MPNSTs. We assessed the C36B11 reactivity pattern in a pathologically and genetically well-characterized cohort of 68 MPNSTs, spanning various clinical presentations, such as type 1 neurofibromatosis (NF1), radiotherapy, and sporadic MPNSTs. We found that 69% (n=47) of all MPNSTs demonstrated loss of H3K27me3 expression, with 42 (61%) showing complete loss and 5 (7%) showing partial loss, whereas 31% (n = 21) retained H3K27me3 expression. Among the NF1-related high-grade MPNSTs, 60% demonstrated loss of expression. In contrast, the majority of both sporadic (95%) and radiotherapy-related (91%) MPNSTs showed loss of H3K27me3 expression. Two of the 3 low-grade MPNSTs and all neurofibromas showed retained expression. Furthermore, all 5 epithelioid MPNSTs retained H3K27me3 labeling. The specificity of H3K27me3 loss as a marker for MPNSTs was studied by testing a large spectrum of lesions included in MPNST differential diagnosis, such as spindle/desmoplastic melanomas, synovial sarcomas, myoepithelial tumors, and other mesenchymal neoplasms, all of which retained expression of H3K27me3. We conclude that immunohistochemical analysis of H3K27me3 has good sensitivity and robust specificity for the diagnosis of MPNST, particularly outside of NF1 clinical history, which represents the most challenging diagnostic setting.

Spitz tumors are a group of melanocytic neoplasms with distinct morphological features that tend to affect young individuals. Distinguishing benign from malignant Spitz tumors can be challenging, but cytogenetic and molecular tests have contributed to improvements in diagnostic accuracy. Spitz tumors harbor diverse genetic alterations, including mutations in HRAS, loss of BAP1, or kinase fusions in ROS1, NTRK1, ALK, BRAF, and RET genes. Limited data exist on the correlation between histopathological features and kinase fusions. Here, we describe the histopathological features of 105 Spitz tumors (Spitz nevi and atypical Spitz tumors), comparing lesions according to their immunoreactivity for ALK or NTRK1. Intersecting fascicular growth of fusiform melanocytes was seen in all but one ALK-positive tumor (27 of 28 or 96.4%), whereas it was infrequent in NTRK1-positive tumors (5 of 20 or 25.0%) and tumors negative for both ALK and NTRK1 (96.4% vs 25.0% vs 8.7%, P < .0027). There was a trend toward ALK-positive tumors being amelanotic compared with NTRK1-positive tumors and combined ALK-/NTRK1-negative tumors (89.3% vs 45% vs 47.4%, respectively, P = .1023) and lacking epithelioid cell morphology (0% vs 45.0% vs 41%, respectively, P = .6985). In conclusion, this study confirms that although not specific, the growth pattern of intersecting fascicles of amelanotic fusiform melanocytes is strongly associated with ALK expression.

We recently reported that germline mutations in BAP1 cause a familial tumor syndrome characterized by high penetrance for melanocytic tumors with distinct clinical and histologic features. Melanocytic neoplasms in affected individuals harbored BRAF mutations, showed loss of BAP1 expression, and histologically resembled so-called "atypical Spitz tumors" (ASTs). ASTs are an ill-defined and probably heterogenous group of melanocytic tumors that display histologic features seen in both Spitz nevi and melanomas. Their biological behavior cannot be reliably predicted. In view of the histologic similarities of the familial tumors and ASTs, we hypothesized that a subset of ASTs might harbor genetic alterations seen in the familial tumors. To address this hypothesis, we analyzed 32 sporadic ASTs for BRAF mutations and for BAP1 expression. Nine (28%) sporadic ASTs showed loss of BAP1 expression, of which 8 (89%) had concomitant BRAF mutations. Only 1 of the BAP1-positive ASTs (4%) had a BRAF mutation (P

Cutaneous melanomas are characterized by a range of histological appearances, and several morphological variants have been described. In this study, we report a variant of superficial spreading melanoma that is characterized by large, irregular junctional melanocytic nests. The junctional nests varied in shape and size, showed focal tendency to confluence, and were often surrounded by a cuff of epidermal keratinocytes. The melanocytes comprising the nests showed variable cytological atypia. In most of the cases, scant intraepidermal or junctional single melanocytes were seen, and other well-documented diagnostic criteria for melanoma were lacking, and as a result, histological recognition of these tumors as melanoma was difficult. Some cases were associated with an invasive dermal component or showed evidence of sun damage. To provide supporting evidence for malignancy, we analyzed these tumors for genomic aberrations. Using array comparative genomic hybridization (aCGH), we identified multiple genomic aberrations in all analyzed cases. A similar pattern of genomic aberrations was seen in a control group of bona fide superficial spreading melanomas, suggesting that these 'melanomas composed exclusively or predominantly of large nests' are indeed variants of superficial spreading melanoma. Fluorescence in-situ hybridization (FISH) was positive in 40% of the cases. However, using aCGH, the FISH-negative cases showed multiple genomic aberrations in regions that are not covered by FISH. The low sensitivity of the FISH test can be explained by the fact that FISH only evaluates four genomic loci for aberrations, whereas aCGH surveys the entire genome. In summary, we present histological and molecular genetic evidence for a morphological variant of superficial spreading melanoma. Awareness of the histological features will aid in their correct diagnosis as melanoma, and in difficult cases, judicious application of ancillary tests such as aCGH (rather than FISH) will assist accurate diagnosis.

Common acquired melanocytic nevi are benign neoplasms that are composed of small, uniform melanocytes and are typically present as flat or slightly elevated pigmented lesions on the skin. We describe two families with a new autosomal dominant syndrome characterized by multiple, skin-colored, elevated melanocytic tumors. In contrast to common acquired nevi, the melanocytic neoplasms in affected family members ranged histopathologically from epithelioid nevi to atypical melanocytic proliferations that showed overlapping features with melanoma. Some affected individuals developed uveal or cutaneous melanomas. Segregating with this phenotype, we found inactivating germline mutations of BAP1, which encodes a ubiquitin carboxy-terminal hydrolase. The majority of melanocytic neoplasms lost the remaining wild-type allele of BAP1 by various somatic alterations. In addition, we found BAP1 mutations in a subset of sporadic melanocytic neoplasms showing histological similarities to the familial tumors. These findings suggest that loss of BAP1 is associated with a clinically and morphologically distinct type of melanocytic neoplasm.

Melanoma arising in the uveal tract (choroid, ciliary body and iris) is the most common intraocular malignant tumor [1]. The incidence of uveal melanoma (UM) in the US population is approximately f...

Summary Background Eruptive Spitz naevi have been reported rarely in the literature. In solitary Spitz naevi, BRAF and HRAS mutations, as well as increased copy numbers of chromosome 11p have been identified. Objectives To investigate the genetic changes underlying eruptive Spitz naevi. Methods We report on a 16-year-old boy who developed multiple disseminated eruptive Spitz naevi within a few months. We analysed BRAF, HRAS, KRAS and NRAS genes in 39 naevi from this patient for hotspot mutations. Furthermore, comparative genomic hybridization analysis was performed in three lesions. Results None of the Spitz naevi displayed a mutation in the analysed genes, and no chromosomal imbalances were observed. Conclusions Our results indicate that the typical genetic alterations described in solitary Spitz naevi appear to be absent in eruptive Spitz naevi. Yet unknown alternative genetic alterations must account for this rare syndrome.

Recently, initial studies describing the use of multicolor fluorescence in situ hybridization (FISH) for classifying melanocytic skin lesions have been published demonstrating a high sensitivity and specificity in discriminating melanomas from nevi. However, the majority of these studies included neither histologically ambiguous lesions nor a clinical long-term follow up. This study was undertaken to validate a special multicolor FISH test in histologically ambiguous melanocytic skin lesions with known clinical long-term follow up. FISH was scored by three independent pathologists in a series of 22 melanocytic skin lesions, including 12 ambiguous cases using four probes targeting chromosome 6p25, centromere 6, 6q23, and 11q13. The FISH results were compared with array comparative genomic hybridization data and correlated to the clinical long-term follow up (mean: 65 months). Pair-wise comparison between the interpretations of the observers showed a moderate to substantial agreement (kappa 0.47-0.61). Comparing the FISH results with the clinical behavior reached an overall sensitivity of 60% and a specificity of 50% (chi(2)=0.25; P=0.61) for later development of metastases. Comparison of array comparative genomic hybridization data with FISH analyses did not yield significant results but array comparative genomic hybridization data demonstrated that melanocytic skin lesions with the development of metastases showed significantly more chromosomal aberrations (P

BACKGROUND Uveal melanoma is the most common intraocular cancer. There are no effective therapies for metastatic disease. Mutations in GNAQ, the gene encoding an alpha subunit of heterotrimeric G proteins, are found in 40% of uveal melanomas. METHODS We sequenced exon 5 of GNAQ and GNA11, a paralogue of GNAQ, in 713 melanocytic neoplasms of different types (186 uveal melanomas, 139 blue nevi, 106 other nevi, and 282 other melanomas). We sequenced exon 4 of GNAQ and GNA11 in 453 of these samples and in all coding exons of GNAQ and GNA11 in 97 uveal melanomas and 45 blue nevi. RESULTS We found somatic mutations in exon 5 (affecting Q209) and in exon 4 (affecting R183) in both GNA11 and GNAQ, in a mutually exclusive pattern. Mutations affecting Q209 in GNA11 were present in 7% of blue nevi, 32% of primary uveal melanomas, and 57% of uveal melanoma metastases. In contrast, we observed Q209 mutations in GNAQ in 55% of blue nevi, 45% of uveal melanomas, and 22% of uveal melanoma metastases. Mutations affecting R183 in either GNAQ or GNA11 were less prevalent (2% of blue nevi and 6% of uveal melanomas) than the Q209 mutations. Mutations in GNA11 induced spontaneously metastasizing tumors in a mouse model and activated the mitogen-activated protein kinase pathway. CONCLUSIONS Of the uveal melanomas we analyzed, 83% had somatic mutations in GNAQ or GNA11. Constitutive activation of the pathway involving these two genes appears to be a major contributor to the development of uveal melanoma. (Funded by the National Institutes of Health and others.).

Blastic plasmacytoid dendritic cell neoplasm (BPDCN) is a neoplasm derived from precursors of plasmacytoid dendritic cells. Cutaneous involvement represents often the first manifestation of the disease. We studied 45 skin biopsies from 33 patients (M:F=7.25:1; median age: 71 y; age range: 30 to 89) with BPDCN to delineate histopathologic and immunophenotypic features of this disease. Patients presented with generalized (n=18), localized (n=6), or solitary (n=9) macules, plaques, and/or tumors. Staging investigations at presentation were negative in 20 patients. Unusual histologic features included a perivascular/periadnexal pattern (6 biopsies from 4 patients) and the presence of pleomorphism of neoplastic cells with blastoid cells admixed with elongated, twisted, or hyperchromatic cells (observed in 24 specimens). Negativity of 1 among the 4 markers CD4, CD56, CD123, and TCL-1 was seen in 11 biopsies, and of 2 markers in 4 biopsies. Staining for CD68 revealed positivity of the majority of cells in 1 and of scattered cells in 24/37 stained cases. Terminal deoxynucleotidyl transferase was observed in 22/37 stained cases. Staining for Bcl-6, MUM-1 and FOX-P1 revealed positivity of a variable proportion of neoplastic cells in 16/30, 19/29, and 21/23 cases, respectively. Our study shows that cutaneous lesions of BPDCN display a greater variability of morphologic and phenotypic features than recognized earlier. Discrete perivascular infiltrates, pleomorphic morphology of neoplastic cells, and unusual phenotypic profiles may be the source of diagnostic pitfalls. These atypical variants should be recognized to make an early diagnosis and to manage properly patients with this aggressive hematological disorder.

Cutaneous lymphomas represent a heterogeneous group of malignant lymphoid diseases with particular tropism for the skin. Prognosis and treatment depend on the type of lymphoma, thus precise diagnosis and classification are of paramount importance. Classification of cutaneous lymphomas relies on a synthesis of all available information, including clinical history and presentation, histopathology, immunophenotype, and molecular data. Thanks to the efforts of the lymphoma groups of both the World Health Organization (WHO) and the European Organization for Research and Treatment of Cancer (EORTC), a joint WHO-EORTC classification for primary cutaneous lymphomas has been proposed in 2005. The WHO-EORTC classification has been adsorbed with minor changes in the 2008 WHO classification of tumours of haematopoietic and lymphoid tissues, thus including for the first time primary cutaneous lymphomas as distinct subtypes of extranodal lymphomas in a general classification of lymphomas.

Despite the introduction of universal newborn hearing screening (UNHS), unilateral hearing loss (UHL) is sometimes recognized late. This diagnostic delay has adverse repercussions, given the importance of binaural hearing for the development of normal auditory processing. It is incorrect to maintain that unilateral hearing is the minimum requirement for adequate speech development and that hearing aid provision is consequently unnecessary. In our retrospective study, hearing aid provision resulted in improved directional and selective hearing (quiet and noisy environments) and, compared with their chronically ill counterparts, the children in our study displayed superior health-related quality of life (HRQoL) scores in all areas. On the basis of the results, the authors conclude that even mild hearing losses (from an auditory threshold of 30 to 40 dB) should have the opportunity for hearing aid provision. A selective literature review was conducted in PubMed and textbooks and with reference to national and international guidelines. Early diagnosis and treatment of UHL have a positive effect on verbal-cognitive, linguistic, communicative, and socio-emotional development, as demonstrated by neurophysiological studies. Among the treatment modalities with differing effects on the quality of binaural hearing, cochlear implants are now used increasingly in children with hearing loss bordering on deafness.Published evidence and clinical experience support early diagnosis and treatment. Wherever feasible, hearing aid provision before or at the end of the first year of life is recommended for children with UHL. What is Known: • Almost 30 years ago, poor academic performance was reported in children with unilateral hearing loss (UHL). • Despite improvements in treatment options, it is traditionally held that unilateral hearing is the minimum requirement for adequate speech development and hearing aid provision is unnecessary. What is New: • Academic and behavioral deficits in children with UHL may be mediated by deficiencies in the default mode network. • Published evidence supports the recommendation for hearing aid provision before or at the end of the first year of life in children with UHL.

Activation of oncogenes by mechanisms other than genetic aberrations such as mutations, translocations, or amplifications is largely undefined. Here we report a novel isoform of the anaplastic lymphoma kinase (ALK) that is expressed in ∼11% of melanomas and sporadically in other human cancer types, but not in normal tissues. The novel ALK transcript initiates from a de novo alternative transcription initiation (ATI) site in ALK intron 19, and was termed ALK(ATI). In ALK(ATI)-expressing tumours, the ATI site is enriched for H3K4me3 and RNA polymerase II, chromatin marks characteristic of active transcription initiation sites. ALK(ATI) is expressed from both ALK alleles, and no recurrent genetic aberrations are found at the ALK locus, indicating that the transcriptional activation is independent of genetic aberrations at the ALK locus. The ALK(ATI) transcript encodes three proteins with molecular weights of 61.1, 60.8 and 58.7 kilodaltons, consisting primarily of the intracellular tyrosine kinase domain. ALK(ATI) stimulates multiple oncogenic signalling pathways, drives growth-factor-independent cell proliferation in vitro, and promotes tumorigenesis in vivo in mouse models. ALK inhibitors can suppress the kinase activity of ALK(ATI), suggesting that patients with ALK(ATI)-expressing tumours may benefit from ALK inhibitors. Our findings suggest a novel mechanism of oncogene activation in cancer through de novo alternative transcription initiation.

Desmoplastic melanoma (DM) is a rare variant of melanoma with distinct clinical, histopathologic, and immunohistochemical features. Clinically, DM differs from conventional melanoma by a higher propensity for local recurrence and less frequent metastatic spread to regional lymph nodes. In its pure form, DM has a distinct appearance displaying a low density of fusiform melanocytes in a collagen-rich matrix. While a number of mutations have been identified in primary melanoma, including BRAF, NRAS, GNAQ, GNA11 and KIT, and the occurrence of these mutations has been found to correlate to some extent with the histopathologic features, anatomic site and/or mode of sun exposure, no distinct set of mutations has so far been reported for DM. To study the potential association of neurofibromin (NF1) mutations with DM, we examined 15 desmoplastic and 20 non-desmoplastic melanomas by next-generation sequencing. Mutations of the NF1 gene were found in 14 of 15 (93%) desmoplastic and 4 of 20 (20%) non-desmoplastic melanomas. The high frequency of NF1 mutations in desmoplastic melanomas suggests an important role for NF1 in the biology of this type of melanoma.

Drug resistance invariably limits the clinical efficacy of targeted therapy with kinase inhibitors against cancer. Here we show that targeted therapy with BRAF, ALK or EGFR kinase inhibitors induces a complex network of secreted signals in drug-stressed human and mouse melanoma and human lung adenocarcinoma cells. This therapy-induced secretome stimulates the outgrowth, dissemination and metastasis of drug-resistant cancer cell clones and supports the survival of drug-sensitive cancer cells, contributing to incomplete tumour regression. The tumour-promoting secretome of melanoma cells treated with the kinase inhibitor vemurafenib is driven by downregulation of the transcription factor FRA1. In situ transcriptome analysis of drug-resistant melanoma cells responding to the regressing tumour microenvironment revealed hyperactivation of several signalling pathways, most prominently the AKT pathway. Dual inhibition of RAF and the PI(3)K/AKT/mTOR intracellular signalling pathways blunted the outgrowth of the drug-resistant cell population in BRAF mutant human melanoma, suggesting this combination therapy as a strategy against tumour relapse. Thus, therapeutic inhibition of oncogenic drivers induces vast secretome changes in drug-sensitive cancer cells, paradoxically establishing a tumour microenvironment that supports the expansion of drug-resistant clones, but is susceptible to combination therapy.

Germline loss of function mutations in BAP1 are associated with the development of cutaneous melanocytic tumors with some histopathologic characteristics seen in Spitz nevi. Similar melanocytic tumors occurring in a sporadic setting have been demonstrated to have biallelic loss of BAP1. In some of these sporadic tumors, loss of BAP1 occurs through mutation of one allele and genomic loss of the other. We screened our database of comparative genomic hybridization profiles of ambiguous melanocytic tumors to identify cases with a single genomic event involving loss of the BAP1 locus. The prevalence of tumors with a single genomic event involving loss of BAP1 was 6.7% in our study population. We further characterized the BAP1 status in 17 of these tumors with available additional material, confirming loss of BAP1 in all cases. We describe BAP1 loss in a blue nevus like melanoma and further expand the histopathologic spectrum of spitzoid melanocytic neoplasms with BAP1 loss.

Spitz tumors represent a group of melanocytic neoplasms that typically affects young individuals. Microscopically the lesions are composed of cytologically distinct spindle and epithelioid melanocytes, with a range in the architectural display or the cells, their nuclear features, and secondary epidermal or stromal changes. Recently, kinase fusions have been documented in a subset of Spitz tumors, but there is limited information on the clinical and pathologic features associated with those lesions. Here, we report a series of 17 patients (9 male, 8 female) with spitzoid neoplasms showing ALK fusions (5 Spitz nevi and 12 atypical Spitz tumors). The patients’ ages ranged from 2 years to 35 years (mean = 17; median = 16). Most lesions were located on the lower extremities and presented clinically as polypoid nodules. All tumors were compound melanocytic proliferations with a predominant intradermal growth. Tumor thickness ranged from 1.1 to 6 mm (mean = 2.9 mm; median = 2.5 mm). The most characteristic histopathologic feature of the tumors (seen in all but two lesions) was a plexiform dermal growth of intersecting fascicles of fusiform melanocytes. All but two tumors were amelanotic. All tumors were strongly immunoreactive for ALK. The ALK rearrangements were confirmed in all cases by fluorescence in situ hybridization (FISH) and the fusion partner was determined by quantitative polymerase chain reaction as TPM3 (tropomyosin 3) in 11 cases and DCTN1 (dynactin 1) in 6 cases. None of the eight tumors, which were analyzed by FISH for copy number changes of 6p, 6q, 9p, or 11q met criteria for melanoma. Two patients underwent a sentinel lymph node biopsy, and in both cases melanocytes nests were found in the subcapsular sinus of the node. Array comparative genomic hybridization of these two tumors revealed no chromosomal gains or losses. In conclusion, our study revealed that Spitz nevi/tumors with ALK rearrangement show a characteristic plexiform morphology and that ALK immunohistochemistry and FISH enables the accurate identification of this morphologic and genetic distinct subset of spitzoid neoplasms.

Cutaneous lesions of lupus erythematosus (LE) show a broad spectrum of clinicopathologic features. Histopathologically, besides typical patterns such as interface dermatitis, perivascular lymphocytic infiltrate and dermal mucin deposits, an involvement of the eccrine structures, especially the acrosyringium, may be observed. We describe the case of a 21-year-old woman with a 4-year history of systemic LE, who presented with a 'butterfly' rash over the cheeks as well as erythematous macules on the arms and décolleté. Biopsy from one lesion on the arm revealed interface changes, necrotic keratinocytes and exocytosis of lymphocytes restricted only to the regions of the acrosyringia. The epidermis between affected acrosyringia was normal with no hints of interface dermatitis. The eccrine glands and coils were not affected. In the dermis there were only sparse inflammatory infiltrates. Differential diagnoses such as erythema multiforme, drug eruption and lichen planus could be ruled out because of histopathologic features and clinical presentation. This is an example of a peculiar histopathological variant of cutaneous LE, characterized by exclusive involvement of the acrosyringia. The histopathologic features represent a pitfall in the diagnosis and can be correctly interpreted only upon correlation with clinical data.

Background Extranodal natural killer–/T-cell lymphoma, nasal type (ENKTCL-NT) is a highly aggressive lymphoma and prognosis is usually poor. The genetic background of primary cutaneous cases is poorly understood. Objective We sought to evaluate the clinicopathologic features of cutaneous ENKTCL-NT, and the prognostic significance of genomic copy number alterations. Methods Eight cases of cutaneous ENKTCL-NT (5 primary, 2 secondary, 1 no staging performed), including 2 patients with an unusually prolonged course of 5 and 23 years, were investigated using array comparative genomic hybridization. Results All patients presented with typical clinicopathologic features. Epstein-Barr virus was found in neoplastic cells in all specimens. Copy number alterations were detected in all 8 cases with losses on 6q (37.5% of cases) and 7p (37.5% of cases), and gains on 7q (37.5% of cases) being the most frequent. Complexity of array comparative genomic hybridization profile did not correlate with the course of the disease. However, an increase of copy number alterations was detected in sequential biopsy specimens of 1 long-term survivor. Limitations This was a small case series retrospective study. Conclusion Clinicopathologic features of cutaneous ENKTCL-NT are distinctive. Lower number of copy number alterations cannot be used as predictor for prolonged survival in cutaneous ENKTCL-NT.

Spitzoid neoplasms are a group of melanocytic tumours with distinctive histopathological features. They include benign tumours (Spitz naevi), malignant tumours (spitzoid melanomas) and tumours with borderline histopathological features and uncertain clinical outcome (atypical Spitz tumours). Their genetic underpinnings are poorly understood, and alterations in common melanoma-associated oncogenes are typically absent. Here we show that spitzoid neoplasms harbour kinase fusions of ROS1 (17%), NTRK1 (16%), ALK (10%), BRAF (5%) and RET (3%) in a mutually exclusive pattern. The chimeric proteins are constitutively active, stimulate oncogenic signalling pathways, are tumourigenic and are found in the entire biologic spectrum of spitzoid neoplasms, including 55% of Spitz naevi, 56% of atypical Spitz tumours and 39% of spitzoid melanomas. Kinase inhibitors suppress the oncogenic signalling of the fusion proteins in vitro. In summary, kinase fusions account for the majority of oncogenic aberrations in spitzoid neoplasms and may serve as therapeutic targets for metastatic spitzoid melanomas. Spitzoid neoplasms constitute a spectrum of melanocytic tumours, characterized by distinct clinical, pathological and genetic features. Here, Wiesner et al. show that kinase fusions represent the majority of oncogenic aberrations in spitzoid neoplasms and may serve as therapeutic targets for metastatic spitzoid melanoma.