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The fifth edition of the World Health Organization (WHO) Classification of Tumors of the Central Nervous System has identified many new tumor types and has established, for the first time, essential and desirable diagnostic criteria for each of them. Among these, genetic alterations play an important role associated with morphology. For the first time, epigenetic data can also constitute essential and/or desirable criteria. These genetic abnormalities can be fusions, deletions or gains/amplifications and can thus be detected by fluorescence in situ hybridization techniques. The purpose of this article is to present the advantages and limitations of this technique in reference to its specific use within neuro-oncopathology in light of the 2021 WHO classification., (Copyright © 2023 Elsevier Masson SAS. All rights reserved.)

Diagnostic updates, an increased precision of tumor sub-type classification and the development of new diagnostic biomarkers (immunohistochemistry (IHC), Fluorescence in situ hybridization (FISH) and other molecular pathology techniques), have a significant impact on pathologists' management of tissue samples. The objective of this work was to test and validate the FISH technique on detached IHC slides. An IHC technique was first performed on 30 tissue samples. After detachment of the lamella, a FISH technique was then performed according to the usual protocol with a centromeric probe. A validation cohort (n=10) with duplicate testing using a traditional FISH technique and an IHC slide with a detached lamella was then carried out. Finally, a cohort of 20 "old" cases (IHC carried out over 2years ago) was also tested. Different types of probes (specific locus, break apart) have been used. All the slides were interpreted by a technician and a pathologist. Evaluation criteria were: the general interpretability of the slide ; the percentage of labeled nuclei; intensity of the signal and the presence or absence of autofluorescence. FISH was interpretable in 100% of recently treated cases and 90% of "old" cases with a satisfactory intensity and a high percentage of labeled nuclei, without autofluorescence. The results of our study show that the reuse of IHC slides for performing FISH is a powerful means of economizing tissue samples, especially for small samples and in the absence of archived representative material., (Copyright © 2022 Elsevier Masson SAS. All rights reserved.)

We report the case of a 79 year-old woman, who was admitted in the department of digestive surgery for an occlusive syndrome. The abdominopelvic computed tomography revealed a voluminous mass infiltrating the uterus, the bladder and the colon. A monobloc surgery is performed. The histopathological examination evidences an invasion of these organs by a well-differentiated glandular proliferation composed of epithelial cells without atypia stained with keratin 7 and carcinoembryonar antigen, without expression of p16, hormonal receptors and keratin 20. Ki-67 labeling index was low. The diagnosis of minimal deviation gastric mucinous adenocarcinoma was proposed. This is an uncommon neoplasm comprising approximately 1% of all endocervical adenocarcinomas. This is a difficult histopathological which should be known by pathologist. It is correlated to a poor clinical outcome with a high tendency to lymph node and extra-uterine metastases, as illustrated in our observation., (Copyright © 2022 Elsevier Masson SAS. All rights reserved.)

Rapid technical advances in molecular biology allowed for the identification of key genetic alterations in central nervous system (CNS) tumors. Our ever-expanding knowledge of brain tumor genetics and the development of new technologies, such as DNA-methylation profiling, required an update of the 2016 fourth edition of the WHO classification of CNS tumors. Updates were regularly published by the Consortium to Inform Molecular Practical Approaches to CNS Tumor Taxonomy-Not Official WHO (c-IMPACT-NOW) until the publication of the fifth edition of the WHO classification of CNS tumors in 2021. In that edition, new types and subtypes are introduced and criteria for histo-molecular diagnostic and grading are refined, especially for diffuse gliomas. The definition of a broad category "diffuse glioma, pediatric subtype" (low or high grade) is a major improvement of the classification. Moreover, the nomenclature was simplified and aligned with that of other blue books. The 2021 edition truly advances the role of molecular diagnostics in CNS tumor classification. Methyloma profiling may become a cornerstone of CNS tumor diagnostic. The new WHO classification will lead to better management of brain tumor patients., (Copyright © 2021 Elsevier Masson SAS. All rights reserved.)

We report the case of a 74-year-old woman who, as part of the follow-up for two breast cancers, presented a 2cm long lung nodule. A microscopic examination of the biopsy under a scanner showed a proliferation of epithelial appearance but whose immunophenotypic profile did not permit a precise diagnosis (negativity of CK7, GATA3, TTF1, negative estrogen receptors but positive progesterone receptors). Wedge resection surgery was performed. Extemporaneous and definitive microscopic examination showed a well-defined lesion made up of lobules of cohesive-looking cells, frequently forming coils. The tumor cells showed some intranuclear inclusions and a few psammomas while the immunohistochemical study showed diffuse expression of EMA, SSTR2A and progesterone receptor markers and a low proliferation index. A diagnosis of a pulmonary localization of a meningioma was proposed. The radiological assessment of the entire neuraxis did not show any other lesion leading to the final diagnosis of primary intra-pulmonary meningioma. This is an exceptional tumor with a difficult histopathological diagnosis of biopsy material, which must familiar to the pathologists. It is associated with an excellent prognosis. Our observation aims to illustrate the macroscopic and microscopic aspects and to present the data from the recent literature review., (Copyright © 2021 Elsevier Masson SAS. All rights reserved.)

Introduction: The department of neuropathology of Sainte-Anne Hospital uses zinc-formalin as the fixative agent for its samples. No publication referenced in Pubmed has proven the validity of this fixative agent. In the context of the accreditation of our standard staining (HPS for Hemalun-Phloxin-Saffron), we started a file for the validation of this method in which the fixative agent constitutes an « interfering » substance which can modify the quality of the technique. The aim of this study was to prove that the use of zinc-formalin as a fixative agent is as suitable as the fixation with 4 % buffered formalin., Materials and Methods: A cohort of samples fixed by zinc-formalin and by 4 % buffered formalin was performed on fresh samples, then cut and stained by HPS. The slides were interpreted by three pathologists (one of them was outside our centre)  ``blind '' to the fixative agent and they evaluated four criteria (general quality of the staining, components of the extracellular matrix, cytoplasmic details, and nuclear details) and scored them (from 0 to 3) according to the Association française en assurance qualité (AFAQAP) recommendations., Results: The cohort included 43 samples. The results of the analysis showed that for samples fixed by zinc-formalin, three of the four criteria obtained significantly a better score than the samples fixed by classical formalin., Discussion and Conclusions: Our results show that the zinc-formalin fixative does not constitute an  ``interfering '' agent for the quality of the HPS staining for neuropathological samples., (Copyright © 2020 Elsevier Masson SAS. All rights reserved.)

We report the case of a 32-year-old man, who was admitted for a recurrent pneumopathy. The thoracic computed tomography revealed a small well-circumscribed lesion of the lower right lobe of the lung. Microscopic examination from the biopsy material of the endoscopy concluded a mucoepidermoid carcinoma. A lobectomy was realized. Microscopic examination revealed the presence of a well-delineated lesion composed of glands and cysts containing mucous and limited by mucous and cylindric and ciliated cells without atypia. The proliferation index was very low. A diagnosis of mucous gland adenoma was made. It is an exceptional tumor and is very difficult to diagnose on biopsy material but should be known by pathologists. It is associated with a good prognosis. The aims of our observation are to present the macroscopic and microscopic features of this tumor and data from recent literature review to better diagnose it. This is also the second observation with molecular details for this entity., (Copyright © 2020 Elsevier Masson SAS. All rights reserved.)

Diffuse gliomas with MYB or MYBL1 alterations are rare tumours mostly affecting children or young adults with long-term epilepsy. This category of glioma includes two morphological subtypes. The angiocentric subtype is characterized by an angiocentric pattern of growth and a frequent MYB:QKI fusion. The isomorphic subtype corresponds to a highly differentiated astrocytic glioma with low cellularity, low proliferation and no specific microscopic features. The diagnosis is based on the imaging, demonstrating a supratentorial tumor, associated with the confirmation of a MYB or MYBL1 rearrangement. Here, we report the case of a 7-year-old child who presented a right frontal brain lesion corresponding to an isomorphic diffuse glioma with MYBL1 alteration., (Copyright © 2020 Elsevier Masson SAS. All rights reserved.)

We report the case of a Caucasian 73-year-old woman, without medical history, who is operated of two lesions of the forehead and the scalp measuring 0.4 and 1cm. There is no adenopathy. Histopathological examination revealed a diffuse vascular proliferation of the dermis and the hypodermis composed of small vessels bordered of plump "epthelioid" endothelial cells. There is no mitotic figure. The stroma is slightly fibrous accompanied by a polymorphic inflammatory infiltrate rich in lymphocytes, sometimes arranged in lymphoid follicles, plasma cells and eosinophils. The proposed diagnosis is angiolymphoid hyperplasia with eosinophilia. This is a rare vascular tumor, benign according with the OMS classification and preferentially observed in the skin. We report a cutaneous case, clinical and histopathological data of the reported cases and present the main differential diagnoses., (Copyright © 2018 Elsevier Masson SAS. All rights reserved.)

We report the case of a 57-year-old man, who is hospitalized for the surgery of a gallbladder mass associated by an increase in fluorodeoxyglucose-activity on positron emission tomography/computed tomography scan. This is an incidental finding occurring during monitoring of a skin melanoma. A cholecystectomy is performed. Microscopic examination identified an infiltration of the gallbladder wall by a proliferation of atypical pigmented spindled melanocytes with numerous mitoses. The immunohistochemical analysis confirmed the melanocytic nature of this proliferation with the staining of HMB-45, S100 protein and Melan-A. A complementary immunohistochemical (p16, desmin and BRAFV600E) and molecular (BRAF sequencing) study is performed. The results are consistent with the hypothesis of a gallbladder metastasis of a cutaneous melanoma is proposed. Gallbladder metastases of melanoma are exceptional. The aim of our work is to describe a new case with immunohistochemical and molecular characterization, to review the literature on this topic and to consider the main differential diagnosis (primary malignant melanoma of the gallbladder)., (Copyright © 2017 Elsevier Masson SAS. All rights reserved.)

We report the case of a 63-year-old healthy patient who was admitted for surgery of a suprasellar tumor with extension to the optic chiasm responsible of visual disturbance. Histopathological examination revealed a tumoral proliferation composed of epithelioid cells without atypia arranged in cords in a mucinous matrix surrounded by some lymphocytic inflammatory infiltrates. On immunohistochemistry, the neoplastic cells strongly expressed GFAP and CD34, a weak expression of EMA, an expression of TTF1 without immunoreactivity for brachyury. Ki-67 labeling index was low around 1%. The diagnosis of chordoid glioma was made. Surprisingly, tumor cells expressed IDH1R132H but molecular analysis did not reveal any mutation of IDH1/2 genes. There was no expression of p53 but high overexpression of EGFR. Chordoid glioma is a rare and low-grade entity. The precise histogenesis remains debated. Our case is unusual because of the infiltration of the optic chiasm and because of the immunoexpression of IDH1R132H without underlying mutations of IDH1/2 genes., (Copyright © 2017 Elsevier Masson SAS. All rights reserved.)

Rhino-sinusal infections are serious diseases and possibly lethal. When they are invasive, we easily discuss apergilloses and mucormycoses. The confirmation of the diagnosis of mucormycosis need an extensive surgery for precise histopathological and mycological evaluation. The pathologist may be faced to other rare mycoses such as phaeohyphomycoses, which present different morphological features than mucormycoses and Aspergillus. Once the diagnosis is established, an appropriate antifungal treatment is quickly started. The aim of our work is to report two observations of phaeohyphomycoses, to describe their histopathological features, to discuss complementary diagnostic methods and to present the main differential diagnoses., (Copyright © 2016 Elsevier Masson SAS. All rights reserved.)

We report the case of a 52-year-old man, who was admitted in the department of otorhinolaryngology for a mass of the right parotid gland. The radiological and clinical hypothesis was a squamous cell carcinoma. Histopathological examination revealed a biphasic proliferation composed of epithelial cells arranged in a tubular pattern stained with cytokeratins 5-6 and 7 and EMA surrounded by clear myoepithelial cells stained with smooth muscle actin and p63. Ki-67 labeling index was low. The diagnosis of epithelial myoepithelial carcinoma was proposed. One year after, the patient noticed a centimetric mass of the left parotid gland. The radiological hypothesis was the presence of an intraparotidian lymph node. Histopathological examination showed a second epithelial myoepithelial carcinoma. This is an uncommon neoplasm comprising approximately 1% of all salivary gland tumours, affecting mainly the parotid gland. It is occurring preferably in patients older than 60years old. This is a low-grade malignant tumour with tendency to local recurrence and lymph node metastatic potential. We describe an exceptional bilateral epithelial myoepithelial carcinoma of the parotid gland., (Copyright © 2015 Elsevier Masson SAS. All rights reserved.)

We report the case of an 11-year-old girl, who was admitted for surgery of an epilepsy-associated brain tumor. The radiological and clinical hypothesis was dysembryoplasic neuroepithelial tumor. Histopathological examination revealed a tumoral proliferation composed of spindle-shaped cells with palisade arrangements around vessels. Tumor cells have small, round and regular nuclei without atypia or mitosis. On immunohistochemistry, the neoplastic cells strongly expressed GFAP and showed a characteristic cytoplasmic dot-like staining with EMA (epithelial membrane antigen). Ki-67 labeling index was low. Molecular analysis failed to reveal the V600E mutation of BRAF gene. The patient was free of seizures after surgery. Angiocentric glioma is a rare brain tumor occuring preferably in children and young adults and is associated with seizures. The precise histogenesis remains debated. The treatment of choice is total resection. The prognosis is favorable if totally resected., (Copyright © 2015 Elsevier Masson SAS. All rights reserved.)