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Intraocular lymphoma is a rare neoplasm that occurs only in the eyes and/or central nervous system. Diagnosis of intraocular lymphoma is difficult because its clinical manifestations mimic chronic uveitis. Pathological examination of the vitreous is one of the main diagnostic tools for intraocular lymphoma, but this is challenging due to the sparse cellularity and specimen degeneration. Here, we reviewed 33 cell block preparations from vitreous perfusion fluid in order to examine the significance of cytopathological findings for differential diagnosis using vitreous samples. The cases comprised 12 intraocular lymphomas and 21 non-lymphomatous diseases. Cytologically, vitreous samples from non-lymphoma cases showed lower cellularity than the lymphoma cases. Whereas vitreous material from cases with infectious endophthalmitis showed prominent neutrophilic infiltration, material from sarcoidosis cases showed infiltration of small lymphoid cells, especially CD4-positive T cells. On the other hand, lymphoma cases showed higher cellularity, with large, irregular and atypical lymphoid cells, frequent necrotic cells in the background, and less pronounced neutrophil infiltration. Immunocytochemically, 11 of the 12 lymphoma cases were of the B-cell phenotype and the remaining case was of the T/NK-cell phenotype. In conclusion, careful cytopathological examination or immunocytochemistry of vitreous material facilitates appropriate diagnosis of intraocular lymphoma. [ABSTRACT FROM AUTHOR]

Background: Desmoplastic small round cell tumor (DSRCT) is a rare soft tissue tumor that generally involves the retroperitoneum, pelvis, omentum and mesentery in younger patients. However, extra-abdominal DSRCT is very rare. Case presentation: A 49-year-old Japanese man noticed a mass in the right parotid gland. Ultrasound examination revealed a solid tumor about 2 cm in diameter. Computed tomography (CT) of the whole body revealed no other tumors or lymph node swelling. Superficial parotidectomy was performed. Histologically, the tumor was composed of various-sized tumor cell nests in an abundant fibromyxoid and collagenous background. The tumor cells were small to medium-sized. Immunohistochemistry showed that the tumor cells were immunoreactive for epithelial markers and desmin. They also showed strong nuclear staining with a Wilms tumor 1 (WT1) antibody detecting the C-terminal region (C-WT1), but not the N-terminal region (N-WT1). We also performed 3′/5′ expression imbalance assay based on reverse transcription polymerase chain reaction (RT-PCR) to determine whether aberrant WT1 gene expression was present. This tumor was found to lack 5′-regional expression of the WT1 gene, as well as immunoreactivity with the N-WT1 antibody. Finally, fluorescence in situ hybridization (FISH) and RT-PCR analyses revealed the presence of a gene showing fusion between exon 7 of EWSR1 and exon 8 of WT1. The tumor was diagnosed as a DSRCT of the right parotid gland. The patient has been followed for 3 years without recurrence or metastasis. Conclusions: Although DSRCT in the salivary gland is extremely rare, it should be included in the differential diagnosis of poorly differentiated salivary gland neoplasms, especially with a fibromyxoid background. Pathologists should bear in mind that DSRCT may occur in major salivary glands and should perform immunohistochemistry with appropriate antibodies, not only those against keratin and desmin, but also one detecting the C-terminal region of WT-1. Furthermore, molecular detection of EWSR1-WT1 fusion gene conclusively confirmed the diagnosis of DSRCT in this uncommon location. [ABSTRACT FROM AUTHOR]

The development of next-generation sequencing (NGS) has enabled the discovery of cancer-specific driver gene alternations, making precision medicine possible. However, accurate genetic testing requires a sufficient amount of tumor cells in the specimen. The evaluation of tumor content ratio (TCR) from hematoxylin and eosin (H&E)-stained images has been found to vary between pathologists, making it an important challenge to obtain an accurate TCR. In this study, three pathologists exhaustively labeled all cells in 41 regions from 41 lung cancer cases as either tumor, non-tumor or indistinguishable, thus establishing a "gold standard" TCR. We then compared the accuracy of the TCR estimated by 13 pathologists based on visual assessment and the TCR calculated by an AI model that we have developed. It is a compact and fast model that follows a fully convolutional neural network architecture and produces cell detection maps which can be efficiently post-processed to obtain tumor and non-tumor cell counts from which TCR is calculated. Its raw cell detection accuracy is 92% while its classification accuracy is 84%. The results show that the error between the gold standard TCR and the AI calculation was significantly smaller than that between the gold standard TCR and the pathologist's visual assessment ( p < 0.05 ). Additionally, the robustness of AI models across institutions is a key issue and we demonstrate that the variation in AI was smaller than that in the average of pathologists when evaluated by institution. These findings suggest that the accuracy of tumor cellularity assessments in clinical workflows is significantly improved by the introduction of robust AI models, leading to more efficient genetic testing and ultimately to better patient outcomes. [ABSTRACT FROM AUTHOR]

A 5‐year‐old girl presented with headache and vomiting. Head computed tomography and magnetic resonance imaging showed a right frontal lobe tumor with marked calcification. The patient underwent resection surgery with suspicion of anaplastic ependymoma, and the tumor was gross totally removed. Pathological examination revealed areas of dense tumor cells with a high nucleocytoplasmic ratio and myxoid areas consisting of tumor cells with a round‐shaped nucleus and eosinophilic cytoplasm. Perivascular pseudorosette, necrosis, circumscribed growth, and microcalcification were also observed. Immunohistochemistry demonstrated negative staining for glial fibrillary protein and epithelial membrane antigen. Diagnosis of a high‐grade neuroepithelial tumor (HGNET) with BCL6 corepressor (BCOR) alteration was made based on pathological findings and internal tandem duplication in the exon 15 of BCOR. Although calcification on radiological and pathological examination is not typical, it would be essential to recognize that calcification could appear in HGNET‐BCOR. [ABSTRACT FROM AUTHOR]

Lymphoepithelioma‐like carcinoma is a poorly differentiated carcinoma with prominent lymphoid infiltration occurring in various organs but is exceedingly rare in the colorectal region. This malignancy is frequently associated with Epstein–Barr virus (EBV). Here we report a case of EBV‐associated lymphoepithelioma‐like carcinoma of the cecum in an 84‐year‐old male who presented with occult blood. In situ hybridization for EBV‐encoded small RNAs (EBER) in an endoscopic submucosal dissection specimen showed that the tumor consisted of EBER‐negative well‐differentiated tubular adenocarcinoma and EBER‐positive lymphoepithelioma‐like carcinoma. Real‐time PCR detected 7.16 copies of the EBV genome per cell in a sample microdissected from the latter component. Genotyping analysis demonstrated EBV genotype 1, and viral protein/transcript expression in the tumor showed EBV latency I. Expression of Ephrin receptor A2, a recently reported receptor for EBV, was demonstrated in the tumor cells by immunohistochemistry. To our knowledge, this is the first report of lymphoepithelioma‐like carcinoma in the colorectal region showing a definite association with EBV infection. [ABSTRACT FROM AUTHOR]

Backgrouund: For patients with any kind of atypical squamous intraepithelial lesion of the uterine cervix or vagina, colposcopy and punch biopsy are common procedures for histological determination following cytology. However, colposcopy-guided biopsy does not provide a high level of diagnostic accuracy. The aim of this study was to determine the usefulness of optical biopsy in vivo using endocytoscopy compared with conventional procedures using colposcopy.Methods: Between May 2018 and March 2019, patients who were scheduled for cervical conization or mapping biopsies of the vagina were prospectively enrolled. Endocytoscopy was performed by senior endoscopists prior to scheduled procedures, and endocytoscopic images and biopsy samples were taken from the most prominent site and surrounding area of the cervical or vaginal lesions. The collection process of images was randomized and anonymous, and three doctors separately evaluated the images according to the ECA classification. ECA 4 and 5 are indicative of endoscopic malignancy. The primary endpoint was diagnostic accuracy (benign or malignant: cervical intraepithelial neoplasia (CIN) 3 or vaginal intraepithelial neoplasia (VAIN) 3 or worse) of cell images at the most prominent site in each patient.Results: A total of 28 consecutive patients were enrolled. Sensitivity, specificity, positive predictive value, negative predictive value and accuracy of endocytoscopic images were 95.0% (84.8-98.6%), 87.5% (61.9-96.5%), 95.0% (84.8-98.6%), 87.5% (61.9-96.5%) and 92.9% (78.2-98.0%), respectively. Inter-observer agreement among three reviewers was 0.78 (0.08-9.88, P < 0.01). On the other hand, the accuracy of colposcopy-guided biopsy was 74.1% (64.0-84.0%).Conclusions: Optical cell diagnosis of cervical or vaginal intraepithelial neoplasia using endocytoscopy provides a high level of diagnostic accuracy.Trial Registration: The study was registered with the UMIN database (ID: 000031712 ). UMIN000031712 . Registered 16 March 2017. [ABSTRACT FROM AUTHOR]

Dear Editor, Eccrine poroma (EP) is a benign cutaneous neoplasm that arises from an intraepidermal eccrine duct. Based on the histopathological findings, the brown globules represent the nest of the tumour cells containing the pigments, and the pinkish-red areas represent the components of the tumour and vessels. [Extracted from the article]

The present study describes the case of a patient with refractory diabetic cystoid macular edema who underwent vitrectomy with en bloc removal of the cystoid lesion component. The current study also performed histopathological and immunohistochemical analyses of the cystoid lesion component to assess fibrin/fibrinogen and advanced glycation end-products (AGEs) immunoreactivity. A 69-year-old Japanese man presented with visual loss in the left eye due to residual cystoid macular edema (CME) refractory to anti-vascular endothelial growth factor therapy. Best-corrected visual acuity was 1.2 in the right eye (OD) and 0.5 in the left eye (OS). Fundus examination showed dot hemorrhages and hard exudates in the peri-macular region with pan-retinal photocoagulation scars in both eye. Swept-source optical coherence tomography revealed CME with slight hyperreflectivity in the cyst OS. A total of 3 months after the initial visit, pars plana vitrectomy was performed, and the translucent solidified component within the cystoid lesion was isolated. Histopathologically, the excised component was elliptical in shape, measuring 0.7x0.4 mm and exhibited homogeneous eosinophilic material without cellular components. No membranous structure was observed surrounding the component. Immunohistochemistry demonstrated that the tissue was positive for fibrin/fibrinogen and weakly positive for AGEs, but was negative for glial fibrillary acidic protein, type 1 collagen and receptor for AGEs. To the best of our knowledge, the present case report is the first to histopathologically examine the contents of refractory CME, and to immunohistochemically demonstrate that fibrin in diabetic CME may be post-translationally modified by AGEs. These results suggested that fibrin in CME may escape degradation by plasmin due to post-translational modifications. [ABSTRACT FROM AUTHOR]

Lipoblastoma can arise almost anywhere within the soft tissues, especially in the extremities. It is rarely seen retroperitoneally. A 3-year-old girl presented with a palpable abdominal mass underwent an exploratory laparotomy with resection of the retroperitoneal mass. Based on histopathologic and cytogenetic features, a final diagnosis of lipoblastoma was rendered. At 18-month follow-up, she had no evidence of recurrence. [ABSTRACT FROM AUTHOR]

Key Clinical Message Causes of intrauterine fetal death ( IUFD) are uncertain in most placental mesenchymal dysplasia ( PMD) cases. Our case showed high α-fetoprotein levels in the maternal circulation, markedly dilated subchorionic vessels, and neonatal hemoglobin concentration of 8.4 g/ dL, suggesting that fetal anemia may explain some adverse outcomes in PMD pregnancies. [ABSTRACT FROM AUTHOR]