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International audience; YAP1-NUTM1 fusion transcripts have been recently reported in poroma and porocarcinoma. NUTM1 translocation can be screened by nuclear protein in testis (NUT) immunohistochemistry in various malignancies, but its diagnostic performance has not been thoroughly validated on a large cohort of cutaneous epithelial neoplasms. We have evaluated NUT immunohistochemical expression in a large cohort encompassing 835 cases of various cutaneous epidermal or adnexal epithelial neoplasms. NUT expression was specific to eccrine poromas and porocarcinoma, with 32% of cases showing NUT expression. All other cutaneous tumors tested lacked NUT expression, including mimickers such as seborrheic keratosis, Bowen disease, basal cell carcinoma, squamous cell carcinoma, Merkel cell carcinoma, nodular hidradenoma, and all other adnexal tumors tested. Remarkably, NUT expression was more frequent in a distinct morphologic subgroup. Indeed, 93% of poroid hidradenoma (dermal/subcutaneous nodular poroma, 13/14) and 80% of poroid hidradenocarcinoma cases (malignant poroid hidradenoma, 4/5) showed NUT expression, in contrast to 17% and 11% of classic poroma (4/23) and porocarcinoma cases (4/35), respectively. RNA sequencing of 12 NUT-positive neoplasms further confirmed the presence of a YAP1-NUTM1 fusion transcript in all cases, and also an EMC7-NUTM1 gene fusion in a single case. In the setting of a cutaneous adnexal neoplasm, nuclear expression of NUT accurately and specifically diagnosed a specific subgroup of benign and malignant poroid tumors, all associated with a NUTM1 fusion, which frequently harbored a poroid hidradenoma morphology.

International audience; Spitz nevi are indolent melanocytic tumors arising preferentially during and after childhood. Over the last decades, recurrent oncogenic drivers, sparsely detected in melanoma, were identified in Spitz melanocytic proliferations. Therefore, the detection of such drivers appears as a relevant diagnostic tool to distinguish both entities. Interestingly, morphologic features might correlate with the oncogenic drivers. Thus, the goal of this study was to assess the performances of previously identified morphological criteria to predict the presence of specific drivers. In total, 352 Spitz melanocytic proliferations either with a genetically identified oncogenic driver or investigated for ALK, ROS1, and NTRK1 overexpression by immunohistochemistry were enrolled in the present study. The microscopic features of the cases were assessed blindly with regards to the molecular status and, performances of previously described morphological criteria to predict the molecular status were assessed applying the likelihood-ratio test (LHR). Overall, an oncogenic driver was identified in 76% of the cases (n = 268/352). No microscopic features allowed the reliable prediction of ROS1- and NTRK1-overexpressing cases. By contrast, a plexiform pattern can contribute to the recognition of ALK-overexpressing cases (LHR(+) = 6.14). Importantly, the pseudo-schwannoma variant was highly suggestive of NTRK3-rearranged cases (LHR(+) = 43). Moreover, atypical/malignant tumor (LHR(+) = 5.18), severe cellular atypia (LHR(+) = 5.07), and p16 loss (LHR(+) = 14) contribute to the recognition of MAP3K8-rearranged cases, while the presence of a sheet-like architecture (LHR(+) = 5.39) and a marked fibrosis of the stroma (LHR(+)=5.06) were predictive of BRAF-fused tumors. To conclude, our study confirms ALK-overexpressing, NTRK3-, MAP3K8-, and BRAF-rearranged cases harbored distinct morphologic features allowing their microscopic recognition.

A series of seven novel thiazolium-based ionic liquids have been synthesized and characterized. To understand the physicochemical properties of thiazolium ionic liquids the compounds were characterized via thermogravimetric analysis, differential scanning calorimetry, and powder X-ray diffraction. The thiazolium sulfur atom is found to impart unique intermolecular interactions affecting the properties of the materials, both in the solid and liquid state. These interactions are examined by Hirshfeld surface analysis of single-crystal X-ray diffraction data as well as via variable-temperature viscometry. Further, it was observed that several of the ionic compounds exhibit high enthalpies of fusion making them potential candidates for thermal energy storage materials, expanding the possible applications for this class of compounds.

The authors describe a case of a 5 cm mixed desmoplastic melanoma occurring on the cheek of an 88-year-old white woman. The epidermis showed the features of lentigo maligna. Within the dermis, there was a mixed desmoplastic melanoma with 2 components. The first component consisted of infiltrative malignant spindled cells with prominent stromal fibrosis and had the typical appearance of desmoplastic melanoma. The second component was within the deep half of the tumor and consisted of a densely cellular nodule composed of spindled melanocytes admixed with many osteoclast-like giant cells. There was a peripheral neurotropism and tumor invaded bone. The Breslow thickness was 14 mm. On followup, a sacral metastasis was discovered, which had a similar morphology to the deep cellular nodule. Immunohistochemistry of spindled cells both inside and outside the nodule showed S100 positivity with the absence of other melanocytic markers (HMB-45, Melan-A). Smooth muscle actin and p63 were focally positive. The osteoclast-like giant cells expressed CD68 and MiTF. Array comparative genomic hybridization of the typical desmoplastic melanoma region had a flat profile, whereas the cellular osteoclast-like giant cell–rich region displayed important cytogenetic anomalies, some of which have been previously described in melanomas. The main array comparative genomic hybridization findings were confirmed by fluorescence in situ hybridization using specific probes. The differences in morphology and molecular cytogenetics between the 2 areas suggest that these might represent the progression or emergence of a more aggressive clone within the tumor. Subsequent metastatic spread to the bone may be a result of accumulated cytogenetic abnormalities.

Primary angiosarcoma of the breast is a rare malignant tumour that presents in young women as a painless mass or a sensation of fullness in the breast. To report two cases of primary breast angiosarcoma presenting with unusual and misleading cutaneous lesions. A clinical investigation including ultrasound, MRI and histological examination. In the first patient, the lesion appeared as a superficial, acquired angioma; in the second as an indolent superficial haematoma. This type of primary presentation is exceptional and the benign appearance of the lesion, combined with a lack of breast mass, is misleading. The benign appearance and the pathological aspect of these lesions can lead to misdiagnosis. Comparison of clinical and pathological data is necessary to prevent delay in diagnosis. We believe that all acquired angiomatous lesions developing on the breasts of young women should raise suspicion of angiosarcoma.

Necrotizing Infundibular Crystalline Folliculitis (NICF) is rare entity of unknown pathogenesis presenting as follicular crystalline papules arising in seborrheic areas. We report 2 cases of NICF in patients under targeted therapy for metastatic adenocarcinoma. In one case, the lesions reappeared cyclically every 3 weeks after each injection and in the other case, lesions persisted until disruption of the continuous oral therapy. Punch-biopsies demonstrated folliculitis with a plugging crystalline material associated with either bacteria or yeast. These are the first descriptions of drug-induced NICF.

BRCA-1-associated protein 1 (BAP1) is a tumor suppressor gene located at chromosome position 3p21.1. It encodes a nuclear protein involved in multiple cellular activities: transcriptional regulation, chromatin modulation and DNA repair [1]. Germline mutations in BAP1 are responsible for a tumor predisposition syndrome (OMIM database #614327) [2]. Carriers are at greater risk of developing cutaneous and ocular melanomas, clear-cell renal cancer, mesothelioma and multiple basal cell carcinomas [3]. [...]

AIMS: Aggressive epidermotropic cutaneous CD8+ lymphoma is currently afforded provisional status in the WHO classification of lymphomas. An EORTC Workshop was convened to describe in detail the features of this putative neoplasm and evaluate its nosological status with respect to other cutaneous CD8+ lymphomas.METHODS & RESULTS: Sixty-one CD8+ cases were analysed at the workshop; clinical details, often with photographs, histological sections, immunohistochemical results, treatment and patient outcome were discussed & recorded. Eighteen cases had distinct features and conformed to the diagnosis of aggressive epidermotropic cutaneous CD8+ lymphoma. The patients typically present with widespread plaques and tumours, often ulcerated and haemorrhagic, and have striking pagetoid epidermotropism histologically. A CD8+ CD45RA+ CD45RO- CD2- CD5- CD56- phenotype, with 1 or more cytotoxic markers was found in 7/18 with a very similar phenotype in the remainder.. The tumours seldom involve lymph nodes but mucosae and central nervous system involvement are not uncommon. The prognosis is poor, with a median survival of 12 months. Examples of CD8+ mycosis fungoides, lymphomatoid papulosis and Woringer-Kolopp presented the typical features well documented in the CD4+ forms of those diseases.CONCLUSIONS: Aggressive Epidermotropic Cutaneous CD8+ Lymphoma is a distinct lymphoma that warrants inclusion as a distinct entity in future revisions of lymphoma classifications. This article is protected by copyright. All rights reserved.

Trichoblastoma is a benign cutaneous adnexal tumor, composed mostly of follicular germinative cells. Its pigmented variant is colonized by numerous dendritic melanocytes. So far, only one case in the literature describes a combination of trichoblastoma and melanoma. We report the case of a 62-year-old man who had a slow-growing mass of the left flank present since childhood. This 8-cm mass was surgically removed when it became ulcerated and associated with axillary lymph nodes. Histologically, this tumor was strictly dermal and composed of 2 intermingled components. Large sheets of atypical, proliferating epithelioid cells predominated. Dispersed solid nests or cribriform epithelial islets encased in fibrous tissue were also seen. Some nests displayed a massive colonization by pigmented dendritic melanocytes. On immunohistochemical staining, the sheets of atypical cells expressed focally but strongly S100 protein, MelanA, HMB45, and MiTF. Epithelial structures diffusely expressed pancytokeratin AE1/AE3, KL1, and pleckstrin homology-like domain, family A, member 1. Based on these results, we diagnosed an intradermal melanoma, possibly developed from dendritic melanocytes colonizing a giant pigmented trichoblastoma. Direct sequencing of the melanoma revealed a rarely described NRAS mutation c.34GT (G12C). Array comparative genomic hybridization displayed a complex profile somewhat divergent from standard melanoma profiles. The patient died of widespread metastatic disease 8 months after initial diagnosis.

A case of primary adenocarcinoma of the renal pelvis occurring in a 57-year-old woman who had no previous history is reported. The lesions were thought to be a renal destruction by pyelolithiasis upon symptomatology and imaging study data. A nephrectomy was thus performed. Macroscopic examination revealed voluminous and exophytic lesions surrounding lithiasis. Diagnosis of intestinal-type adenocarcinoma of the renal pelvis was established on histological examination. No evidence of other tumor localization was revealed by complete exploration. Primary adenocarcinoma of renal pelvis is a rare and often mucinous intestinal-type tumour. Chronic inflammation and renal lithiasis seem to be associated with this tumour. Few cases are reported and prognosis is doubtful. The main differential diagnosis to eliminate is secondary lesions to the kidney of adenocarcinoma from another origin. A careful pathological examination in case of pyelonephritic kidney is necessary to look for an associated tumour.

e14677 Background: BRAF V600E mutations are rare in colorectal cancers, being present in less than 10% of the cases. The prognosis of BRAF mutant tumors seems heterogeneous but usually poor, especi...

Context.—Adenocarcinomas of the sinonasal tract are classified into 4 categories: salivary-type, intestinal-type, nonintestinal-type, and metastatic. Signet-ring cell carcinoma is the rarest form of intestinal-type adenocarcinoma. Only isolated cases have been reported in the literature. Objective.—To evaluate clinical attributes, morphology, and immunohistochemistry in signet-ring cell carcinoma of the sinonasal tract. Design.—Seventy-three cases of primary sinonasal adenocarcinomas were retrieved from the files. Only 5 signet-ring cell adenocarcinomas (tumors composed of more than 90% signet-ring cells) were identified. In all cases, clinical data and histologic slides were available and were reviewed. Consecutive tissue sections were immunostained with monoclonal antibodies against MUC2, MUC5AC, MUC5B, MUC6, p53 protein, and MIB-1. Results.—Four of our 5 patients were woodworkers. They were treated by surgical excision and radiotherapy. Patient follow-up ranged from 11 to 84 months. Three patients presented an unfavorable evolution and died of metastatic spread. Microscopically, the tumors produced abundant mucin deposits, which accumulated in large extracellular pools. Tumor cells were predominantly signet-ring cells floating in the pools of mucin. The mucins profile was MUC2+, MUC5AC+, MUC5B+, and MUC6−. Eighty percent of cells were immunostained by p53 protein antibody and 60% cells with MIB-1 antibody. Conclusions.—The mucin profile is similar to the profile described in digestive tract adenocarcinoma. It is not useful to differentiate between metastatic adenocarcinoma and primary intestinal-type sinonasal adenocarcinoma. Clinical data and immunochemistry with p53 protein and MIB-1 confirm that sinonasal signet-ring cell carcinoma is a high-grade and aggressive tumor.

Nous rapportons l’observation d’un patient âge de 66 ans, sans antecedent majeur, hospitalise pour une oligo-arthrite accompagnee de purpura vasculaire, evoluant par poussees. Le bilan biologique detectait une cryoglobuline mixte monoclonale de type IIa, une dysglobulinemie monoclonale IgM Kappa et une activation du complement (effondrement des fractions CH 50, C1, C2, C4). La serologie de l’hepatite C etait negative. La biopsie cutanee permettait d’observer une vasculite leucocytoclasique. Secondairement, le patient devait presenter des manifestations renales, sous la forme d’une hematurie macroscopique associee a une proteinurie sans insuffisance renale. La biopsie renale mettait en evidence une proliferation mesangiale discrete, une infiltration du flocculus par une majorite de cellules macrophagiques et un aspect en double contour des parois capillaires, sans pseudo-thrombi. L’ensemble de ces lesions faisait porter le diagnostic de glomerulonephrite membrano-proliferative de type I, compatible avec une atteinte renale dans le cadre d’une cryoglobulinemie. Il n’y avait pas de proliferation extra-capillaire associee ni de lesion de vascularite. L’interstitium etait depourvu d’infiltrat lymphomateux. En immunofluorescence, il existait des depots sous-endotheliaux d’IgM, d’IgG et de C3. L’endoscopie digestive haute, realisee dans le cadre du bilan etiologique, retrouvait une gastrite d’aspect suspect de la petite courbure et du fundus. Microscopiquement, la muqueuse gastrique etait le siege d’un infiltrat lymphomateux a petites cellules de phenotype B de type MALT, justifiant la mise en route d’une chimiotherapie associant Chloraminophene et Rituximab. Les cryoglobulines de type II ont deux composants : une immunoglobuline monoclonale, habituellement IgM Kappa, ayant une activite anticorps (facteur rhumatoide) contre le composant polyclonal (IgG le plus souvent) de la cryoglobuline ; elles surviennent dans la quasi-totalite des cas chez des patients porteurs du virus de l’hepatite C. Les autres causes de cryoglobulinemie mixte sont les maladies auto-immunes et les lymphoproliferations B, en premier lieu le lymphome malin non hodgkinien de type lymphocytique (LLC-B). Au plan physiopathologique, la production de cryoglobulines par les cellules lymphomateuses entraine l’apparition d’une glomerulonephrite membrano-proliferative a complexes immuns circulants. Des arguments experimentaux suggerent un role pathogene direct des cryoglobulines dans la pathogenie des lesions glomerulaires. A notre connaissance, l’atteinte renale dans le cadre d’une cryoglobulinemie, revelant un lymphome de type MALT gastrique n’a jamais ete decrite dans la litterature. Cette possibilite justifie la realisation d’une endoscopie digestive haute dans le bilan etiologique.