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The goal of this article is to emphasize the role of anatomopathology for the intratumoral detection of the immune checkpoint PD-L1. This molecule is one of the main targets in the anti-cancer immunotherapy. The binding of PD-L1 to its receptor PD-1 results in the inactivation of the cytotoxic T-cells, thus providing a mechanism of keeping immune reactions under control. This process can be circumvented by tumour cells to evade immune system. By blocking PD-1/PD-L1 binding, it is possible to reactivate T-cells targeting tumour neo-antigens. This article focuses on how PD-L1 works, on its implication in neoplastic processes, on the general principles of its therapeutic blockade, on the biomarkers underlying the treatment efficacy and on the practical implications of these biomarkers, especially in the anatomopathological practice.

Background: Although increasing data supports the use of transbronchial lung cryobiopsies (TBLCs) for the diagnosis of diffuse parenchymal lung diseases (DPLDs), its role as an alternative to surgical lung biopsy (SLB) is still under debate. The aim of this study was to assess the benefit of additional SLBs performed in selected patients after TBLCs., Method: We conducted a multicentric Belgian prospective trial in which SLBs were performed after TBLCs when the pathological diagnosis was uncertain or if a nonspecific interstitial pneumonia (NSIP) pattern was observed hypothesizing that SLB could provide additional information and that a co-existent UIP pattern could be missed., Results: Eighty-one patients with TBLCs performed for a DPLD were included in the study between April 2015 and December 2019. A specific histological diagnosis was obtained in 52 patients (64%) whereas no pathological diagnosis following TBLCs was obtained in 13 patients (16%) and a pattern suggestive of a NSIP was observed in 16 patients (20%). Fourteen out of these 29 patients had SLBs after TBLCs. SLBs showed a UIP pattern in 11 (79%), a pattern suggestive of a hypersensitivity pneumonitis in two (14%) and a NSIP pattern in one patient (7%). Among the 16 patients with pathological NSIP following TBLCs, six underwent a SLBs showing a UIP in five and confirming a NSIP in one patient only. A retrospective pathological analysis of patients having both procedures showed a lower diagnostic confidence and agreement among pathologists for TBLCs compared to SLBs. Major factors underlying the added value of SLBs were the bigger size of the sample as well as the subpleural localization of the biopsies., Conclusions: TBLCs are useful in the setting of DPLDs with a good diagnostic yield. However, our study suggests that SLB provides critical additional information in case TBLCs are inconclusive or show a pattern suggestive of a NSIP, questioning the accuracy of TBLC to adequately identify this histological pattern.

Non-specific Interstitial Pneumonia (NSIP) is an anatomo-clinical entity within the group of Diffuse Infiltrative Pulmonary Diseases (DPID). It is very rarely found in pediatrics. Main symptoms are dry cough and dyspnea. Bronchoalveolar lavage and biology are non specific. The thoracic CT scan suspects the diagnosis, but histological examination of a lung biopsy remains the reference examination and makes the diagnosis highly probable according to the ATS / ERS criteria. An autoimmune assessment should be performed because NSIPs are often associated with connective tissue disease or may even be the first sign of connectivitive tissues diseases. The treatment of the acute phase is mainly based on the administration of corticosteroids and the prognosis is generally good. In this article, we describe the management of NSIP, based on a pediatric clinical case.

Gene fusions involving TFE3 defines the "Xp11.2 translocations" subclass of renal cell carcinomas (RCCs) belonging to the MiT family translocation RCC. Four recurrent TFE3 fusion partners were identified to date: PRCC, ASPSCR1, SFPQ, and NONO. Break-apart TFE3 fluorescence in situ hybridization (FISH) on formalin-fixed and paraffin-embedded (FFPE) tissue sections is currently the gold standard for identification of TFE3 rearrangements. Herein, we report a case of RCC with a morphological appearance of Xp11.2 translocation, and positive TFE3 immunostaining. By FISH, the spots constituting the split signal were barely spaced, suggestive of a chromosome X inversion rather than a translocation. We performed RNA-seq from FFPE material to test this hypothesis. RNA-seq suggested a fusion of RBM10 gene exon 17 (Xp11.23) with TFE3 gene exon 5 (Xp11.2). RBM10-TFE3 fusion transcript was confirmed using specific RT-PCR. Our work showed that RNA-Seq is a robust technique to detect fusion transcripts from FFPE material. A RBM10-TFE3 fusion was previously described in single case of Xp11.2 RCC. Although rare, RBM10-TFE3 fusion variant (from chromosome X paracentric inversion), therefore, appears to be a recurrent molecular event in Xp11.2 RCCs. RBM10-TFE3 fusion should be added in the list of screened fusion transcripts in targeted molecular diagnostic multiplex RT-PCR. © 2016 Wiley Periodicals, Inc., (© 2016 Wiley Periodicals, Inc.)

An 19-year-old woman was admitted for acute appendicitis. The histological study of the appendix revealed a tubular variant of endocrine carcinoma of the appendix. Neuroendocrine tumors ("NETs") of the appendix are rare tumors which are usually detected incidentally, affecting 0.3% to 0.9% of appendectomies. Depending on their size, but also on some other factors, including histologic type, these tumors will require specific treatment; sometimes appendectomy will not be sufficient.

Intussusception in adults is a rare cause of intestinal obstruction and is usually secondary to some lesion in the gastrointestinal tract. We report a case of intestinal obstruction due to ileo-ileal intussusception, an inflammatory fibroid polyp formed the leading edge of the intussusceptum, which is a rare polypoidal lesion of the gastrointestinal tract.