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Background The rate of growth of primary melanoma is a robust predictor of aggressiveness, but the mutational profile of fast-growing melanomas (FGMM) and the potential to stratify patients at high risk of death has not been comprehensively studied. Objective To investigate the epidemiologic, clinical, and mutational profile of primary cutaneous melanomas with a thickness ≥ 1 mm, stratified by rate of growth. Methods Observational prospective study. Deep-targeted sequencing of 40 melanoma driver genes on formalin fixed, paraffin-embedded primary melanoma samples. Comparison of FGMM (rate of growth > 0.5 mm/month) and nonFGMM (rate of growth ≤ 0.5 mm/month). Results Two hundred patients were enrolled, among wom 70 had FGMM. The relapse-free survival was lower in the FGMM group (P = .014). FGMM had a higher number of predicted deleterious mutations within the 40 genes than nonFGMM (P = .033). Ulceration (P = .032), thickness (P = .006), lower sun exposure (P = .049), and fibroblast growth factor receptor 2 (FGFR2) mutations (P = .037) were significantly associated with fast growth. Limitations Single-center study, cohort size, potential memory bias, number of investigated genes. Conclusion Fast growth is linked to specific tumor biology and environmental factors. Ulceration, thickness, and FGFR2 mutations are associated with fast growth. Screening for FGFR2 mutations might provide an additional tool to better identify FGMM, which are probably good candidates for adjuvant therapies.

International audience; Cutaneous melanomas are exceptional in children and represent a variety of clinical situations, each with a different prognosis. In congenital nevi, the risk of transformation is correlated with the size of the nevus. The most frequent type is lateral transformation, extremely rare before puberty, reminiscent of a superficial spreading melanoma (SSM) ex-nevus. Deep nodular transformation is much rarer, can occur before puberty, and must be distinguished from benign proliferative nodules. Superficial spreading melanoma can also arise within small nevi, which were not visible at birth, usually after puberty, and can reveal a cancer predisposition syndrome (CDKN2A or CDK4 germline mutations). Prognosis is correlated with classical histoprognostic features (mainly Breslow thickness). Spitz tumors are frequent in adolescents and encompass benign (Spitz nevus), intermediate (atypical Spitz tumor), and malignant forms (malignant Spitz tumor). The whole spectrum is characterized by specific morphology with spindled and epithelioid cells, genetic features, and an overall favorable outcome even if a regional lymph node is involved. Nevoid melanomas are rare and difficult to diagnose clinically and histologically. They can arise in late adolescence. Their prognosis is currently not very well ascertained. A small group of melanomas remains unclassified after histological and molecular assessment.

International audience; "Acral FibroChondroMyxoid tumor" (AFCMT) is a recently described distinctive subtype of acral soft tissue tumor that typically arises on the fingers and toes. We herein present the unreported imaging features of AFCMT in a 44-year-old woman. This otherwise healthy patient was referred for a painful, slow-growing, soft tissue mass in the middle finger of her right hand. Initial radiographs and computed tomography showed a small lesion centered in the soft tissue of the ulnar aspect of the proximal phalanx, associated with scalloping of the underlying bone. Magnetic resonance imaging confirmed the presence of a well-circumscribed soft tissue tumor that exhibited relatively high T2-weighted signal intensity and marked enhancement after contrast administration. Subsequent excisional biopsy was performed. Histologically, the tumor was characterized by an abundant stroma displaying fibrous, chondroid, and myxoid areas. By immunohistochemistry, tumor cells stained for CD34, ERG, and focally S100 protein. RNA-sequencing allowed detection of THBS1-ADGFR5 gene fusion which confirmed the diagnosis of AFCMT. At 2-year follow-up, the patient remains free of recurrence. AFCMT is a previously unrecognized entity that may mimic chondroma and should be considered in the differential diagnosis of soft tissue tumors with cartilaginous or myxoid stroma in the extremities.

International audience; Acral soft tissue tumors are common neoplasms, a subset of which pose a diagnostic challenge. We report 10 cases of a previously unrecognized acral benign soft tissue tumor. These tumors arose on the fingers and toes and involved bone in half of cases. Histologically, the tumors were lobulated and displayed an abundant stroma made of variable fibrous, chondroid and myxoid material reminiscent of cartilaginous or myoepithelial differentiation. Tumor cells harbored small round to reniform nuclei with clear chromatin and inconspicuous nucleoli along with scant eosinophilic cytoplasm. The cells were mostly arranged haphazardly in the stroma but also in small clusters. No mitotic activity was detected. No specific feature was identified in recurrent cases. By immunohistochemistry, the cells consistently stained for CD34 (10/10), ERG (9/10), and SOX9 (7/10). Whole RNA sequencing identified a previously undescribed recurrent in frame THBS1-ADGRF5 gene fusion in all cases. The transcript was confirmed by RT-PCR and was not found in the control group of mimickers including soft tissue chondromas. We propose the name of Acral FibroChondroMyxoid Tumors for this new entity.

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Glomerulopathy associated with lecithin-cholesterol-acyltransferase deficiency (LCAT) is a rare automosal recessive disease. Acquired LCAT deficiency due to inhibitory autoantibodies against LCAT are also described. This disease is induced by systemic deposits related to a lipid metabolism disorder and lead to multi-organ involvement including renal involvement. Lipid profile usually shows variable cholesterol levels but very low HDL levels. Here we describe the case of a 33-year-old man presenting a nephrotic syndrome associated with moderate renal insufficiency for which the pathological analysis allowed to guide towards the diagnosis of LCAT deficiency. Laboratory and genetic data confirmed this diagnosis. Familial history and lipid profile abnormalities are important in the identification of this disease.

Diffuse esophageal leiomyomatosis is a rare esophageal tumor characterized by circumferential thickening of smooth muscle layers. Diffuse esophageal leiomyomatosis can be associated with Alport's syndrome and therefore diagnosed by skin biopsy. Alport syndrome is a hereditary disease usually defined by the association of glomerular nephropathy and perceptual deafness. Here we describe the management of a young women with a diffuse esophageal leiomyomatosis and a past history of uterine leiomyoma. The surgical treatment depends on the esophageal extent of the disease. Association between diffuse esophageal leiomyomatosis and early uterine leiomyomas could be also observed and leading to Alport's syndrome diagnosis despite the absence of renal abnormalities.

Surgery of small bowel melanoma metastases has to be reconsidered in the era of targeted treatments and immunotherapy. To retrospectively assess context and outcomes of small bowel melanoma metastases resections. All consecutive melanoma patients who underwent resection of small bowel metastases between 2011 and 2017, in a single referral center, were retrospectively analyzed through melanoma-specific survival (MSS). A total of 20 patients were included with a 47.8 months median follow-up. Before small bowel surgery, eight patients (40%) were asymptomatic while seven had anemia and five patients had abdominal pain. All resections were decided on tumor boards except for three surgeries performed in the emergency setting. In the whole cohort, MSS was 89.5 months with 50% of patients alive at the study endpoint. We classified surgical indications in three groups: (1) surgery as a pivotal treatment for mono- or oligo-metastases limited to the small bowel (n = 6); (2) salvage surgery for symptomatic patients in order to preserve their chances to switch to an active line of medical treatment (n = 8); and (3) surgery of small bowel dissociated metastatic progression for patients otherwise controlled (n = 6), aiming at keeping patients with the same treatment or active follow-up. In these three situations, the objective of surgery was usually met, and most patients had a long median MSS after surgery: 70.3 months, 89.5 months and 72.4 months, respectively. Although medical treatments have dramatically improved survival in metastatic melanoma, surgical control of life-threatening localization like small bowel metastases is often a condition for long survival.

Background Since 2010, nationwide networks of reference centers for sarcomas (RREPS/NETSARC/RESOS) collected and prospectively reviewed all cases of sarcomas and connective tumors of intermediate malignancy (TIM) in France. Methods The nationwide incidence of sarcoma or TIM (2013–2016) was measured using the 2013 WHO classification and confirmed by a second independent review by expert pathologists. Simple clinical characteristics, yearly variations and correlation of incidence with published clinical trials are presented and analyzed. Results Over 150 different histological subtypes are reported from the 25172 patients with sarcomas (n = 18712, 74,3%) or TIM (n = 6460, 25.7%), with n = 5838, n = 6153, n = 6654, and n = 6527 yearly cases from 2013 to 2016. Over these 4 years, the yearly incidence of sarcomas and TIM was therefore 70.7 and 24.4 respectively, with a combined incidence of 95.1/106/year, higher than previously reported. GIST, liposarcoma, leiomyosarcomas, undifferentiated sarcomas represented 13%, 13%, 11% and 11% of tumors. Only GIST, as a single entity had a yearly incidence above 10/106/year. There were respectively 30, 64 and 66 different histological subtypes of sarcomas or TIM with an incidence ranging from 10 to 1/106, 1–0.1/106, or < 0.1/106/year respectively. The 2 latter incidence groups represented 21% of the patients with 130 histotypes. Published phase III and phase II clinical trials (p−6) are significantly higher with sarcomas subtypes with an incidence above 1/106 per. Conclusions This nationwide registry of sarcoma patients, with exhaustive histology review by sarcoma experts, shows that the incidence of sarcoma and TIM is higher than reported, and that tumors with a very low incidence (16/year) are less likely to be included in clinical trials.

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; Background External radiotherapy has become indispensable in oncological therapies. Unfortunately, radiation is responsible for serious side effects, such as radiodermatitis. The skin is weakened and ulcerated. Our study aimed to evaluate the subcutaneous transfer of microfat (MF) alone and two mixes: MF + Platelet-rich plasma (PRP) and MF + stromal vascular fraction (SVF) to treat radiation-induced skin lesions.Method We defined randomly five experimental groups of nine mice: 1 healthy control group and 4 irradiated (60 Grey) and treated groups. The skin lesions were treated 3 months after irradiation by MF, MF + PRP (50%–50%), MF + SVF (90%–10%) or Ringer-lactate subcutaneous injections. Wound healing was evaluated at 1, 2 and 3 months post-injection and histological wound analysis at 3 months, after euthanasia.Results All the irradiated mice presented with wounds. After sham-injection, the wound area increased by 91.1 ± 71.1% versus a decrease of 15.9 ± 23.1% after MF alone (NS), 27.3 ± 23.8% after MF + SVF (NS) and 76.4 ± 7.7% after MF + PRP (P = 0.032). A significative reduction of skin thickness in wound periphery was measured for the three treated groups compared to sham-injection (P < 0.05) but not in the healed wounds (NS). The most important subcutaneous neo-vessel density was shown after MF + SVF injection.Conclusion The MF + PRP mix was the most efficient product to increase healing. The MF + SVF mix showed the highest rate of neo-angiogenesis but was disappointing in terms of healing.

We report a series of 6 melanocytic proliferations harboring both NRAS and IDH1 hotspot mutations. Clinically, there was no specific sex-ratio, ages ranged from 18 to 85 years, and the trunk and limbs were the most affected localizations. In half of the cases, progressive modification of a pre-existing nevus was reported. Morphologically, all tumors were predominantly based in the dermis and the most striking pathologic finding was the presence of a background architecture of congenital-type nevi with a superimposed biphasic pattern formed by dendritic pigmented melanocytes surrounding areas of nevoid melanocytes. This finding was further underscored by HMB45 staining, which was positive in the dendritic cells and negative in the nevoid melanocytes. Four cases displayed increased cellularity and 1 case showed increased dermal mitotic activity. DNA and RNA sequencing revealed NRAS and IDH1 comutations in all 6 cases, with homogenous expression data according to unsupervised clustering analysis. Array-comparative genomic hybridization revealed no copy number alteration for the 2 most cellular and mitogenic cases. All were surgically excised, available follow-up for 2 patients showed no relapse nor metastases. We hypothesize that the IDH1 mutation is a secondary event in a pre-existing NRAS-mutated nevus and could be in part responsible for the emergence of a pigmented dendritic dermal component. So far, such comutations have been reported in one benign melanocytic nevus and several melanomas. This combination could represent a new subgroup of intermediate prognosis (melanocytoma) with a distinctive morphology. Further acquisition of genomic anomalies could progressively lead to malignant transformation.

A Nodular Pink Lesion with an Uncommon Diagnosis: A QuizMost melanomas are diagnosed by the patients themselves or by their partners or relatives; they alone can describe its history. We designed a prospective cross-sectional study to describe patients' perception of morphology, growth pattern and kinetics of their primary melanoma over 1 mm in thickness before resection. Patients were interviewed with a questionnaire, a grid representing 9 possible scenarios of melanoma growth, and a set of 87 photographs of potential aspects of melanomas and precursors. Most patients were able to describe the growth of their melanoma and select pictures representative of its successive aspects before resection. Among 453 patients, 60% reported a preexisting lesion present for years. Growth pattern scenarios concurred with tumor kinetics but with no statistical difference between nodular and superficial spreading subtypes. These subjective patient-reported indicators about melanoma growth over time could dynamically complement its objective pathological analysis otherwise static at a single time point.

International audience; Pediatric neoplasms with a myofibroblastic differentiation are frequent in children, in particular myofibroma. Recently, a novel deep soft tissue myofibroblastic neoplasm has been described with high cellularity, a smooth muscle phenotype and SRF-RELA fusion. We report the case of a 15-year-old boy who presented with a tumor of the deep soft tissue of the arm, with overlapping histological features with the recently described SRF-RELA group of myofibromas but differing by the presence of calcifications, a novel SRF-STAT6 fusion transcript and nuclear expression of STAT6. No local recurrence nor distant metastasis was detected at the current follow-up of 29 months. The clinical relevance of this novel fusion requires further investigations.

Background: Since 2010, presentation to a designated sarcoma tumor board and pathological review by an expert network are mandatory for sarcoma patients in France. NETSARC+ (merging the 3 initial RREPS, RESOS & NETSARC) collected prospectively all cases of reviewed sarcomas and tumors of intermediate malignancy (TIM) nationwide. We report on the incidence of subtypes according to WHO classification from 2013 to 2016. Methods: Sarcoma or TIM confirmed by review of expert sarcoma pathologists were all prospectively integrated in the database; the results using the latest WHO classification are presented for the years 2013 to 2016, including yearly variations. Correlation of the incidence of each histotype with dedicated published clinical trials was conducted. Results: 139 different histological subtypes are reported among the 25172 patients with sarcomas (n = 18710, 64%) or TIM (n = 6460, 36%), respectively n = 5838, n = 6153, n = 6654, and n = 6527 yearly from 2013 to 2016. Over these 4 years, the observed yearly incidence of sarcomas, TIM, and both was therefore 79.7, 24.9 and 95.1/106/year, above that previously reported. GIST, liposarcoma, leiomyosarcomas, undifferentiated sarcomas represented 13%, 13%, 11% and 11% of all sarcomas. Only GIST, as a single entity exceeded a yearly incidence above 10/million per year. There were respectively 30, 63 and 66 different histological subtypes of sarcomas or TIM (single entities or lumped together, e.g. MPNST, or vascular sarcomas...) with an incidence ranging from 10 to 1/106/year, 1-0.1/106 per year, or < 0.1/106/year respectively. The 2 later “incidence groups” included 21% of the patients. The incidence of 8 histotypes varied significantly over this 4 years. Patients with tumors with an incidence above 1/106 per year have significantly higher numbers of dedicated published phase III and phase II clinical trials (p < 10-6). Conclusions: This nationwide registry of sarcoma patients with an histology reviewed by sarcoma experts shows that the incidence of sarcoma and TIM is higher than previously reported, may vary over years for some histotypes, and that tumors with an incidence < 10e6 have a much lower access to clinical trials. Funding Statement: NetSARC (INCA & DGOS) and RREPS (INCA & DGOS), RESOS (INCA & DGOS) and LYRICAN (INCA-DGOSINSERM 12563), Institut Convergence PLASCAN (17-CONV-0002), Association DAM’s, Ensemble contre Le GIST, Eurosarc (FP7-278742), la Fondation ARC, Infosarcome, InterSARC (INCA), LabEx DEvweCAN (ANR-10-LABX-0061), Ligue de L’Ain contre le Cancer, La Ligue contre le Cancer, EURACAN (EC 739521) funded this study. Declaration of Interests: The funders had no role in the study design, data collection, data analysis, data interpretation, or writing of the report.

The infiltration by numerous osteoclastic giant cells is a frequent finding in bone tumors and pseudo-tumors. Pathologists must integrate clinical and radiological data to achieve a correct diagnosis in bone pathology. Benign giant-cell rich lesions of bone encompass giant cell tumor of bone, aneurysmal bone cyst, chondroblastoma, brown tumor and fibrous cortical defect/non-ossifying fibroma. Amongst malignant neoplasms, variants of conventional osteosarcoma, undifferentiated pleomorphic sarcoma, leiomyosarcoma and bone metastasis must be discussed. Recently, new diagnostic markers, antibodies for immuno-histochemistry and genetic markers, have been developed and are helpful to diagnose such lesions.

Resume Nous rapportons le cas d’une patiente de 33 ans operee pour un teratome mature kystique. L’examen histologique retrouvait deux kystes dont un teratome mature et un struma ovarii avec une composante carcinomateuse papillaire. La cancerisation des struma ovarii est visible dans 5 a 10 % des cas, le plus souvent sous la forme d’un carcinome papillaire. Le diagnostic est rarement fait en preoperatoire, les patientes ne presentant une symptomatologie thyroidienne que dans d’exceptionnels cas. Au niveau histologique, la tumeur se presente de facon identique a ce que l’on peut observer dans un carcinome thyroidien et des mutations de BRAF ont ete decrites. Le probleme se pose avec une metastase ovarienne d’un carcinome thyroidien. Un bilan thyroidien normal et la presence de tissu thyroidien normal au contact de la tumeur intra-ovarienne sont en faveur d’un struma ovarii cancerise. La prise en charge therapeutique n’est pas consensuelle allant d’une annexectomie a une hysterectomie avec annexectomie bilaterale. Les patientes doivent etre suivies au long cours avec des dosages de thyroglobuline pendant au moins 10 ans et la realisation de scintigraphie corps entier a l’iode 123 pour detecter une recidive, voire des metastases. Le pronostic est souvent bon mais des criteres precis restent encore a definir.

The diagnosis of malignant peripheral nerve sheath tumor remains challenging, especially in the sporadic setting. Malignant peripheral nerve sheath tumor is a rare malignancy, and owing to the lack of specific histological criteria, immunohistochemical and molecular diagnostic markers, several differential diagnoses must be considered, in particular melanoma. Recently, inactivation of the polycomb repressive complex 2 (PRC2), induced by inactivating mutations in two of its critical constituents SUZ12 and EED, was reported in a large subset of malignant peripheral nerve sheath tumors. Homozygous PRC2 inactivation induces complete loss of trimethylation at lysine 27 of histone 3 (H3K27me3). Recent studies suggest that complete loss of H3K27me3 is highly specific for malignant peripheral nerve sheath tumor and may be a useful immunohistochemical diagnostic marker. Therefore, to determine the specificity of the complete loss of H3K27me3 expression in the context of the differential diagnosis of malignant peripheral nerve sheath tumor from melanoma (its major potential mimic), we performed H3K27me3 immunohistochemistry in a pathologically and genetically well-characterized cohort of primary (neurofibromatosis type 1 (NF1), radiation-associated and sporadic context) malignant peripheral nerve sheath tumors (n=122) and in a cohort or primary (desmoplastic) and metastatic melanomas (n=265). In total, 88 (72%) malignant peripheral nerve sheath tumors, including 46 (71%) NF1-associated, 4 (100%) radiation-associated, and 38 (72%) sporadic tumors, showed complete loss of H3K27me3. We observed increased loss of H3K27me3 with increasing histological grade. Interestingly, we found complete loss of H3K27me3 in 37% (n=98) of all melanomas, including 25% (n=9) of primary desmoplastic melanomas. Moreover, partial loss ('mosaic' pattern) was observed in 23 (19%) of all malignant peripheral nerve sheath tumors and in 136 (51%) of all melanomas. Complete loss of H3K27me3 detected by immunohistochemistry is not specific for malignant peripheral nerve sheath tumor and cannot be used safely when distinguishing malignant peripheral nerve sheath tumor from melanoma.

Aims: Assess the impact of radiation doses to neural stem cell (NSC) niches in patients with IDH-wild-type glioblastoma.Materials and Methods: Fifty patients were included in the study. NSC niches [SubVentricular Zone (SVZ) and Sub Granular Zone (SGZ)] were contoured by fusing CT scans and pre-therapy MRI, Tumor location defined ipsilateral and contralateral SVZ and SGZ. Prognostic significance of clinical, biological and dosimetric parameters were examined. We generated a Recursive Partitioning Analysis (RPA) model with independent prognostic classes.Results: Median follow-up: 23.8 months. Event free and overall survival (OS): 10 and 19.1 months. Incomplete surgery, PTV (planning target volume), ipsilateral SVZ or NSC niche mean dose > 57.4 Gy, contralateral NSC niche mean dose > 35 Gy and bilateral NSC niche mean dose > 44 Gy were significantly correlated with reduced OS. Only EGFR amplification was an independent prognostic factor (p = 0.019) for OS. RPA generated independent risk groups: 1 (low risk): [ipsilateral NSC mean dose (INMD) < 58.01 Gy and methylated MGMT promoter], 2: (INMD < 58.01 Gy and unmethylated MGMT promoter and contralateral SVZ mean dose < 18.6 Gy; p = 0.43), 3: (INMD < 58.01 Gy and unmethylated MGMT promoter and contralateral SVZ mean dose > 18.6 Gy; p = 0.002) and 4: (very high risk) (INMD > 58.01 Gy; p < 0.001).Conclusion: High radiation doses to ipsilateral NSC and contralateral SVZ could have a negative impact on overall survival in IDH-wild-type glioblastoma population.

International audience; 716 IDH2 mutations are commonly associated with 1p/19q codeletion in diffuse adult gliomas Diffuse gliomas are classified according to the 2016 World Health Organization (WHO) Classification of Tumors of the Central Nervous System, 1 which combines histological and molecular features. Diagnosis requires the assessment of mutations in the isocitrate dehydrogenase genes (IDH1 and IDH2), key genetic alterations characterizing gliomas with favorable outcome. 2 Because IDH1 and IDH2 are highly similar enzymes, the WHO classification, as most of the current studies, combines these mutations into the same molecular group; however, it is unclear whether these tumors share the same characteristics. We analyzed data from 1517 patients included in the French POLA Network to investigate differences between IDH1-and IDH2-mutant gliomas. Inclusion criteria were the written consent of the patient for clinical data collection and genetic analysis and sufficient material for molecular studies allowing classification according to the 2016 WHO classification. IDH1-R132H mutational status was evaluated using automated immunohistochemistry in all cases (n = 1517). Direct sequencing 3 was performed in 978 cases and demonstrated IDH mutation in 573 cases (this includes confirmation of IDH1-R132H mutation in 468 cases, other IDH1 mutations in 61 cases, and IDH2 mutation in 44 cases). The 1p/19q codeletion status was determined based on single nucleotide polymor-phism arrays, comparative genomic hybridization arrays, and/ or microsatellite marker analysis. 3 The following data were recorded: age, sex, follow-up, and MRI features (tumor location , extension, contrast enhancement, edema). All statistical analysis was done using IBM SPSS statistics software version 23. Chi-square test was used to compare qualitative variables. Continuous variables were compared using the Mann– Whitney U-test, and the Kaplan–Meier method was used to estimate survival distributions. Among the 1517 patients, 1025 had an IDH-mutant tumor: 96% were IDH1-mutant and 4% IDH2-mutant. Integrated diagnoses are summarized in Fig. 1. The frequency of 1p/19q code-letion was higher in the IDH2-mutant group compared with the IDH1-mutant group (91% vs 48%, P < 0.001). Wang and coworkers previously reported higher frequency of 1p/19q codeletion in IDH2-mutant gliomas (9/18 samples) compared with IDH1-mutant. 4 The percentage of each category in our study does not reflect the normal distribution of glioma because of the inclusion criteria in the POLA Network (ie, high-grade glioma with oligodendroglial component). However, the higher proportion of 1p/19q codeleted glioma in the IDH2-mutant group cannot be attributed to the inclusion criteria. Because the main population of glioma associated with IDH2 mutation was 1p/19q codeleted anaplastic oligodendroglioma, we focused on this subgroup to search for differences compared with IDH1 mutation. Among these patients (n = 474), we did not observe any difference in terms of age, sex, progression free survival, or overall survival between IDH1-and IDH2-mutant tumors. However, IDH2-mutant anaplastic oli-godendrogliomas presented more frequently with multilobar extension (56% of the IDH2-mutant vs 35% of the IDH1-mutant, P = 0.015) and edema (79% vs 57%, P = 0.02). Furthermore, bifrontal location with corpus callosum involvement was more frequent in IDH2-mutant compared with IDH1-mutant tumors (41% vs 16%, P < 0.001). IDH mutation is supposed to be one of the first " hits " of gliomagenesis, 5 resulting in production of an oncome-tabolite, D-2-hydroxyglutarate (D-2HG), which impacts the α-ketoglutarate–dependent dioxygenase functions. Previous studies demonstrated that the potential for IDH-mutant enzymes to produce D-2HG depends on the mutation type. 6 Based on our observations, we could hypothesize that the higher D-2HG accumulation induced by IDH2 mutation may lead to a phenotype that is favorable to 1p/19q chromosomal loss. It may also impact distinct cellular pathways that promote a more invasive phenotype. Whether IDH1 or IDH2 mutations impact distinct glial precursor cells with differential invasive properties remains to be elucidated. In conclusion, our results illustrate that IDH2-mutant glio-mas are commonly associated with 1p/19q codeletion. Most of IDH2-mutant anaplastic oligodendroglioma 1p/19q codeleted are multilobar. Understanding the genomic events involved in these specificities may represent a step forward for therapeutic development.

// Nicolas Macagno 1, 2, * , Frederic Fina 1, 3, * , Nicolas Penel 4 , Corinne Bouvier 1, 2 , Isabelle Nanni 5 , Florence Duffaud 6, 7 , Raquel Rouah 5 , Bruno Lacarelle 8 , L'houcine Ouafik 5 , Sylvie Bonvalot 9 and Sebastien Salas 6, 7 1 Department of Pathology, Assistance Publique Hopitaux de Marseille Timone Hospital, Marseille, France 2 Aix-Marseille University, Medical Faculty, CRO2, UMR 911 (Equipe IV), Marseille, France 3 ID-Solutions, Grabels, France 4 Department of General Oncology, Oscar Lambret Center, Lille, France 5 Department of Molecular Oncology, Assistance Publique Hopitaux de Marseille, Marseille, France 6 Department of Oncology, Assistance Publique Hopitaux de Marseille Timone Hospital, Marseille, France 7 Aix-Marseille University, Medical Faculty, Marseille, France 8 Department of Medical Biology, Assistance Publique Hopitaux de Marseille Timone Hospital, Marseille, France 9 Department of Surgery, Institut Curie, PSL Univeristy, Paris, France * These authors contributed equally to this work Correspondence to: Sebastien Salas, email: sebastien.salas@ap-hm.fr Keywords: ddPCR; cfDNA; CTNNB1; desmoid; prognosis Received: October 27, 2017 Accepted: February 25, 2018 Published: April 06, 2018 ABSTRACT Since desmoid tumors (DT) exhibit an unpredictable clinical course, with stabilization and/or spontaneous regression, an initial “wait-and-see” policy is the new standard of care–thus, the actual challenge is to identify early factors of progression. We present a method of detection of CTNNB1 mutations using a targeted digital droplet PCR (ddPCR) on cell-free DNA (cfDNA) extracted from blood samples of 31 DT patients. Furthermore, we analyzed the correlation between DT evolution and plasmatic concentration of total and mutated cfDNA at the time of diagnosis. Circulating copies of CTNNB1 mutants (ctDNA) were detected in the plasma of 6 patients (33%) but their concentration was not correlated with evolution of the tumor. Concentration of total cfDNA was higher in the plasma of patients with progressive desmoids ( p = 0,0009). Using a threshold 1375, it was possible to predict desmoid evolution for 65% of patients by measuring the quantity of circulating DNA in their plasma as early as the time of diagnosis. Albeit showing that the detection of CTNNB1 mutants is possible in the plasma of patients harboring a desmoid tumor, the results of this preliminary study raise the hypothesis that most of the circulating DNA detected in their plasma is derived from non-neoplastic cells, most likely normal neighboring tissues being actively invaded. Our results open the perspective of using cfDNA as a biomarker to predict prognosis at the time of diagnosis and assess tumor dynamics to optimize the treatment strategy.

International audience; Pilocytic astrocytomas represent the most common glioma subtype in young patients and account for 5.4% of all gliomas. They are characterized by alterations in the RAS-MAP kinase pathway, the most frequent being a tandem duplication on chromosome 7q34 involving the BRAF gene, resulting in oncogenic BRAF fusion proteins. BRAF fusion involving the KIAA1549 gene is a hallmark of pilocytic astrocytoma, but it has also been recorded in rare cases of gangliogliomas, 1p/19q co-deleted oligodendroglial tumors, and it is also a common feature of disseminated oligodendroglial-like leptomeningeal neoplasm. In some difficult cases, evidence for KIAA1549-BRAF fusion is of utmost importance for the diagnosis. Moreover, because the KIAA1549-BRAF fusion constitutively activates the MAP kinase pathway, it represents a target for drugs such as MEK inhibitors, and therefore, the detection of this genetic abnormality is highly relevant in the context of clinical trials applying such new approaches. In the present study, we aimed to use the high sensitivity of Droplet Digital PCR (DDPCR™) to predict KIAA1549-BRAF fusion on very small amounts of formalin-fixed paraffin-embedded tissue in routine practice. Therefore, we analyzed a training cohort of 55 pilocytic astrocytomas in which the KIAA1549-BRAF fusion status was known by RNA sequencing used as our gold standard technique. Then, we analyzed a prospective cohort of 40 pilocytic astrocytomas, 27 neuroepithelial tumors remaining difficult to classify (pilocytic astrocytoma versus ganglioglioma or diffuse glioma), 15 dysembryoplastic neuroepithelial tumors, and 18 gangliogliomas. We could demonstrate the usefulness and high accuracy (100% sensitivity and specificity when compared to RNA sequencing) of DDPCR™ to assess the KIAA1549-BRAF fusion from very low amounts of DNA isolated from formalin-fixed paraffin-embedded specimens. BRAF duplication is both necessary and sufficient to predict this fusion in most cases and we propose that this single analysis could be used in routine practice to save time, money, and precious tissue.

International audience

International audience; Giant congenital melanocytic nevi may be symptomatically isolated, or syndromic. Associations with capillary malformations are exceptional, and development of epidermal cysts has not been described. A 71-year old patient with a giant congenital melanocytic nevus of the lower back, buttocks and thighs was asymptomatic except for unexpected hemorrhage during partial surgical excision years before. Blunt trauma at age 64 initiated recurrent, severe pain under the nevus; multiple large epidermal cysts developed within it. Imaging and biopsy showed a large, non-pulsatile venous malformation intermingled with the deep nevus. A low-abundance, heterozygous BRAF c.1799T>A (p.V600E) mutation was present in both the gluteal and occipital “satellite” nevi; additional mutations in NRAS, GNAQ, GNA11, HRAS and PIK3CA were undetectable. This is the first demonstration of an identical BRAF mutation in multiple congenital nevi from the same individual, confirming genetic heterogeneity in giant nevi. This exceptional case indicates that constitutive activation of BRAF can be an underlying cause of unusual associations of giant nevi with vascular malformations, and that the latter may be included among the somatic RASopathies.

Lysozyme amyloidosis (ALys) is a rare autosomal dominant hereditary systemic amyloidosis associated with a large spectrum of clinical manifestations. ALys phenotype mainly involves the digestive tract, liver and spleen, kidneys, lymph nodes, skin, and lachrymal and salivary glands. Very recently, cardiac involvement and peripheral neuropathy associated with a new p.Leu102Ser variant of lysozyme have been documented. In the present observation, we extend the phenotypic heterogeneity of ALys to the tracheobronchial tree with histologically proven bronchial ALys-amyloid deposits. We report the case of a 62-year-old man of Italian origin (Piedmont) diagnosed with ALys associated with the p.Trp82Arg variant. The patient complained of upper digestive symptoms, sicca syndrome, and lately recurrent pulmonary infections. Thoracic endoscopy revealed a fragile, inflammatory, and granulomatous aspect of the bronchi. Amyloid deposits were observed in the upper digestive tract, salivary glands, temporal artery, and tracheobronchial tree. Symptomatic treatment was offered. Recurrent pulmonary infections occurred during the follow-up. Lung involvement in hereditary ALys has only been exceptionally described. Although vascular involvement has already been reported in ALys in many organs, it never concerned cranial arteries. This case highlights the systemic nature of the amyloid protein variant deposits and expands the spectrum of clinical manifestations to chest involvement. The literature review highlights that hereditary ALys with the p.Trp82Arg variant is frequent in patients coming from Piedmont (Italy). Due to diffuse organs involvement related to ALys, it is important not to misdiagnose ALys for AL amyloidosis, the most frequent form of amyloidosis.

The central nervous system (CNS) high-grade neuroepithelial tumor with BCOR alteration (CNS HGNET-BCOR) is a recently described molecular entity. We report 3 new CNS HGNET-BCOR cases sharing common clinical presentation and pathologic features. The 3 cases concerned children aged 3 to 7 years who presented with a voluminous mass of the cerebellum. Pathologic features included proliferation of uniform spindle to ovoid cells with fine chromatin associated with a rich arborizing capillary network. Methylation profiling classified these cases as CNS HGNET-BCOR tumors. Polymerase chain reaction analysis confirmed the presence of internal tandem duplications in the C-terminus of BCOR (BCOR-ITD), a characteristic of these tumors, in all 3 cases. Immunohistochemistry showed a strong nuclear BCOR expression. In 2 cases, local recurrence occurred within 6 months. The third case, a patient who received a craniospinal irradiation after total surgical removal followed by a metronomics maintenance with irinotecan, temozolomide, and itraconazole, is still free of disease 14 months after diagnosis. In summary, CNS HGNET-BCOR represents a rare tumor occurring in young patients with dismal prognosis. BCOR nuclear immunoreactivity is highly suggestive of a BCOR-ITD. Whether CNS HGNET-BCOR should be classified among the category of "embryonal tumors" or within the category of "mesenchymal, nonmeningothelial tumors" remains to be clarified. Because CNS HGNET-BCOR share pathologic features and characteristic BCOR-ITD with clear cell sarcoma of the kidney, these tumors may represent local variants of the same entity.

Despite being one of the most frequent soft-tissue sarcomas, well-differentiated liposarcoma has never been reported near the spine. The authors present the case of a 67-year-old man with progressive history of back pain. Physical examination revealed a mass located within the right paravertebral muscles. MR and CT imaging showed a heavily ossified central mass surrounded by a peripheral fatty component. No connection with the underlying bone was detected on imagery and during surgery. After surgical resection, histopathological examination revealed a tumor harboring combined features of well-differentiated liposarcoma and low-grade osteosarcoma. Tumor cells displayed overexpression of MDM2, CDK4, and P16 by immunohistochemistry and CGH revealed amplification of 12q13-15 as the only genetic imbalance. MDM2 FISH analysis was performed but was inconclusive. The pathological, immunohistochemical, and genetic features, the differential diagnoses, and the therapeutic management of this unusual tumor are discussed. No complementary treatment was performed initially. Following first treatment, two recurrences occurred 6 and 9 years later, both displaying histological features similar to the first occurrence. Radiotherapy was started after the second recurrence. Follow-up shows no evidence of disease 11 years after initial diagnosis. This case was unusual due to the paravertebral location of the tumor and its divergent differentiation.

International audience; Meningeal solitary fibrous tumors-hemangiopericytomas (SFT-HPC) and ă meningiomas can be difficult to distinguish on histologic examination. ă STAT6 immunohistochemistry (IHC) is a reliable diagnostic marker of ă SFT-HPCs. Recently, GRIA2 has also been reported to be a diagnostic ă marker of SFT-HPC, although no extensive data are available for ă meningeal SFT-HPCs yet. The aim of this study was to test their ă diagnostic performance in a large cohort of SFT-HPCs and meningiomas. ă IHC analyses for GRIA2 and STAT6 were performed on tissue microarrays ă containing 76 SFT-HPCs and 181 meningiomas. Results were compared with ă previous data with ALDH1 and CD34. Two different anti-STAT6 antibodies ă were tested: SC-20 polyclonal and YE361 monoclonal antibody. Ninety-six ă percent of meningeal SFT-HPCs but no meningioma displayed nuclear STAT6 ă positivity. With SC-20 antibody, concomitant cytoplasmic staining for ă STAT6 was observed in > 50% of all cases, including meningiomas. ă However, using YE361 antibody, cytoplasmic staining was absent, and ă nuclear signal intensity was stronger leading to better interpretation ă of STAT6 IHC. GRIA2 was positive in 84% of SFT-HPCs and in 16% of ă meningiomas. STAT6 had excellent sensitivity (96%) and specificity ă (100%), ALDH1 and GRIA2 had same sensitivity (84%), but ALDH1 and CD34 ă had better specificity than GRIA2 (97% and 96% vs. 84%, ă respectively). For the differential diagnosis of SFT-HPCs versus ă meningiomas, the best diagnostic approach is to perform STAT6, followed ă by ALDH1 and CD34 in the case of uncommon STAT6-negative cases. Because ă of meningioma positivity, GRIA2 seems less useful in this indication.

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11063 Background: Since desmoid tumors (DT) exhibit an unpredictable clinical course, with stabilization and/or spontaneous regression, an initial “wait-and-see” policy is the new standard of care to select best indications of active treatments in case of significant evolution. Therefore, translational research is crucial to identify predictive factors of progression. Most DT are characterized by CTNNB1 mutation (CM) in exon 3 (T41A, S45F, S45P). Circulating cell-free tumoral DNA (ctDNA), named "liquid biopsy", has emerged as a new promising non-invasive tool to detect biomarker in several cancers. Methods: We present a method of detection of DT-specific CM using a targeted strategy digital droplet PCR (ddPCR) on cell-free DNA (cfDNA) extracted from blood samples of 31 DT patients (pts). T41A, S45P, S45F and their respective CTNNB1 wild-type probe were designed for ddPCR. Furthermore, we analyzed the correlation of cfDNA levels (CTNNB1 wt/ml plasma) and evolution of the tumor. Results: Initial DT CM statuswas known for 28 pts and unknown for 3 pts. 24 pts presented a CM (17 pts T41A, 6 pts S45F and 1 pt S45P), 2 pts a mutation of APC, 2 pts were wild-type, and 3 pts were undetermined. Among pts with a CM, CTNNB1 mutants were detected in the cfDNA of 6 patients (19.4%). CM detection was not correlated with the quantity of cfDNA analyzed (p = 0,7263–Mann-Whitney (MW)). Absolute quantification of cfDNA (CTNNB1 wt) normalized by mL of plasma displayed higher levels for patients with progressive DT (p = 0,0009 - MW), this difference of cfDNA quantity was also present between progressive, stable and self-regressive DT (p = 0,0012 - MW). A threshold of 875 CTNNB1 copies/mL predicted DT progression with a sensibility of 100% (CI95%: 59-100) and a specificity of 76.5% (CI95%: 50.1-93.2). Absolute cfDNA quantity was also higher in patients harboring multiple desmoids (p = 0.0292 - MW). Conclusions: The absolute quantification of normalized cfDNA is correlated with evolution of the disease, independently of the initial tumor type of CM. This study opens the perspective of using cfDNA as a genomic biomarker to assess the tumor dynamics at initial diagnosis, and to monitor treatment strategy in case of tumor evolution.