Genomic and Pathologic Profiling of Very Well-Differentiated Gastric Adenocarcinoma of Intestinal Type: A Study With Emphasis on Diffuse-Type Transformation.

Very well-differentiated adenocarcinoma of intestinal type is a distinct subtype of gastric cancer characterized by anastomosing glands with a hand-in-hand pattern and low-grade cytologic atypia resembling intestinal metaplasia. This is a slow-growing neoplasm with an indolent clinical course; however, a subset demonstrates transformation into adenocarcinoma with higher-grade histology, typically diffuse-type carcinoma, and behaves aggressively. This study aimed to better characterize the genomic and pathologic features, with a focus on factors associated with diffuse-type transformation. A total of 58 cases with (n=31) and without (n=27) diffuse-type transformation were analyzed for molecular and pathologic features. First, comprehensive deep DNA sequencing was conducted in 18 cases (discovery cohort), followed by a digital droplet polymerase chain reaction of hot spot RHOA mutations in 40 cases (validation cohort). In total, RHOA mutations were the most common alteration (34%), followed by loss of ARID1A (12%), p53 alterations (10%), and CLDN18 :: ARHGAP26/6 fusions (3.4%). FGFR2 amplification was identified in an advanced case with a p53 alteration. Altered p53 expression was recognized only in higher-grade components and was significantly associated with advanced disease ( P =0.0015) and diffuse-type transformation ( P =0.026). A mixed mucin phenotype was also strongly correlated with advanced disease ( P <0.001) and diffuse-type transformation ( P <0.001). Decreased E-cadherin expression was frequently observed (74%) in poorly cohesive components. This study demonstrated that a subset of RHOA -mutant diffuse-type gastric cancers develops through the transformation of very well-differentiated adenocarcinoma of intestinal type. Our observations suggest a mixed mucin phenotype as a risk factor and alterations in p53 and E-cadherin as drivers of diffuse-type transformation.

Carcinomatous Meningitis and Hydrocephalus in Plasmacytoid Urothelial Carcinoma of the Urinary Bladder With Extremely Elevated CA19-9 Levels.

This case report describes a rare and aggressive presentation of plasmacytoid urothelial carcinoma (PUC) with carcinomatous meningitis, hydrocephalus, extensive organ involvement, and extremely elevated serum CA19-9 levels. Autopsy findings revealed that PUC of the urinary bladder origin caused carcinomatous meningitis and hydrocephalus, with exacerbation of hydrocephalus as the direct cause of death. Immunohistochemical studies confirmed the bladder origin of PUC, and PUC cells were positive for CA19-9, a tumor marker commonly associated with gastrointestinal malignancies, suggesting that the markedly high serum CA19-9 level was related to the tumor-producing mechanism.

Orbital Intravascular Natural Killer/T-cell Lymphoma: An Unusual Cause of Ocular Symptoms.

Orbital intravascular lymphoma is rare and typically of B-cell lineage. In this study, we report a patient who developed orbital lesions of intravascular natural killer/T-cell lymphoma (IVNKL), an extremely rare lymphoma. An 88-year-old man presented with rapidly progressive right vision loss and double vision. A neurological examination revealed that he had decreased visual acuity and severe oculomotor impairment in the right eye. Magnetic resonance imaging showed right-dominant, nonmass lesions in both orbits. No lesions were found in the lymph nodes, skin, or brain. The patient received immunosuppressive and antifungal therapy, but his clinical condition rapidly deteriorated, and he died of multiple organ failure. Autopsy revealed natural killer/T-cell lymphoma proliferation within the lumina of small blood vessels in multiple organs, including the ocular adnexa of the right orbit. These findings show that he was ultimately diagnosed with IVNKL. IVNKL could initially cause ocular symptoms due to the involvement of the ocular adnexa. Ocular involvements have not been described previously. Even if patients initially present with only ocular symptoms, IVNKL should be considered.

Autopsy findings of left atrial appendage closure device.

We report an autopsy case of an 80-year-old woman who underwent left atrial appendage closure with a WATCHMAN (Boston Scientific, St. Paul, MN, USA) device. This is the first report of histologic assessment following left atrial appendage closure with a WATCHMAN device at 3 months. Gross and histopathological examinations revealed neoendocardial coverage of the WATCHMAN device. Partial endothelialization was verified by CD34 staining; however, it remains unclear when complete endothelialization is likely to occur.

Metachronous carcinogenesis of superficial esophagus squamous cell carcinoma after endoscopic submucosal dissection: incidence and risk stratification during long-term observation.

BACKGROUND: This study aimed to reveal long-term outcomes, such as incidence of metachronous esophageal and head and neck squamous cell carcinomas and overall survival rate, through long-term observation of patients with esophageal carcinoma post-endoscopic submucosal dissection. METHODS: Risk of metachronous carcinogenesis was evaluated in 88 patients with intramucosal esophageal carcinoma (without history of metachronous esophageal or head and neck squamous cell carcinomas) who underwent endoscopic submucosal dissection from 2007 to 2008 and were endoscopically observed for > 3 years. Histologically, the papillary vessel is defined as the clock gear-like structure composed of capillaries directly penetrating the epithelium (starting from the lamina propria) and covering at least two-thirds of it, around which the tumor cells are arranged in a spiral pattern. RESULTS: Median endoscopic follow-up period was 11.0 years. Cumulative 2-, 5-, and 10-year metachronous esophageal carcinoma rates were 11.4%, 20.6%, and 39.3%, respectively. Stepwise multivariate Cox proportional hazard regression analysis identified multiple Lugol-voiding lesions (LVLs) as the single significant independent predictor. Cumulative 2-, 5-, and 10-year metachronous head and neck squamous cell carcinoma rates were 6.9%, 10.4%, and 19.6%, respectively. Stepwise multivariate Cox proportional hazard regression analysis identified multiple LVLs, Brinkman index, papillary vessel, and younger age as significant predictive factors. Overall post-endoscopic submucosal dissection survival rates were 98.8% and 87.5% at 5 and 10 years, respectively. CONCLUSION: Patients with a history of esophageal carcinoma remain at risk for metachronous carcinogenesis even > 5 years after endoscopic submucosal dissection. Thus, long-term follow-up is important.

Late recurrence of gastric carcinoma 15 years after surgery.

A 70-year-old man who had undergone total gastrectomy 15 years ago for mucinous gastric carcinoma on the lesser curvature of the cardia, visited our hospital complaining of cough. Chest X-ray showed a right hilar shadow and an infiltrative shadow in the left middle lung field, which was not seen in the previous year. Whole-body positron emission tomography-computed tomography (CT) revealed abnormal uptake in the irregular consolidation of the left lung, enlarged right hilar lymph nodes, and a mass lesion on the right adrenal gland. Advanced primary lung adenocarcinoma with multi-organ metastasis was suspected and a CT-guided percutaneous lung biopsy was performed. Histopathological examination showed immunostaining patterns in complete accordance with those of the resected specimen of stomach, and the diagnosis of late recurrence of gastric carcinoma was confirmed. Pulmonary metastasis might have occurred as a direct hematogenous metastasis rather than through the liver. He achieved 31 months survival after the diagnosis receiving some sequences of chemotherapy. Late recurrence over 10 years after gastrectomy is extremely rare and significant predictive factors of late recurrence are not known. We hope that this case will help in detecting significant factors predictive of late recurrence after gastrectomy for gastric carcinoma.

Primary alveolar soft part sarcoma of the rectum resected by endoscopic submucosal dissection: A case report.

Alveolar soft part sarcoma (ASPS) is a very rare soft tissue sarcoma. Primary ASPS of the gastrointestinal tract is especially rare. Due to the scarcity of cases, neither its clinicopathologic features nor its mutational background has been clarified. Here, we report a case of ASPS arising from the rectum, which was completely resected by endoscopic submucosal dissection. The lesion was a 17 × 16 × 15 mm semi-pedunculated mass in the upper portion of the rectum in a 46-year-old female. In terms of histology, tumor cells exhibited confluent eosinophilic cytoplasm, forming a sheet-like architecture. Periodic acid Schiff-positive diastase-resistant intracytoplasmic crystals were observed in the tumor cells. Fluorescence in situ hybridization revealed TFE3 rearrangement, and reverse transcription polymerase chain reaction revealed an ASPSCR1-TFE3 type 1 fusion. Negative PAX8 immunostaining and the absence of other massive lesions in postoperative imaging studies led to a diagnosis of primary ASPS of the rectum. The potential oncogenic role of the canonical ASPSCR1-TFE3 fusion transcript in gastrointestinal ASPS was indicated. Primary gastrointestinal ASPS remains a diagnostic pitfall in routine surgical pathology.

Pancreatic ductal adenocarcinoma with mismatch repair deficiency resected after long-term observation.

Pancreatic ductal adenocarcinoma (PDAC) with mismatch repair (MMR) deficiency is a rare subtype, clinicopathological features of which have not been fully understood. A 70-year-old woman was admitted for the investigation of a 20-mm pancreatic tumor in the pancreatic head, detected during the cause scrutiny of exacerbation of diabetes mellitus and panhypopituitarism. The tumor decreased in size after administration of hydrocortisone for panhypopituitarism. Autoimmune pancreatitis, complicated with hypophysitis, was suspected, and prednisolone treatment was administered. The tumor did not show enlargement for 3 years during which a dose of prednisolone was maintained. However, 1.5 years after the cessation of prednisolone administration, the tumor size increased again. On endoscopic ultrasonography, the tumor was found to be a 25.2-mm mass lesion with almost uniformly low echogenicity and blood flow signal, and anisonucleosis on cytodiagnosis was revealed. Pancreatoduodenectomy was performed, and on histological analysis, moderately differentiated tubular adenocarcinoma with massive lymphocytic infiltration was observed. Immunohistochemistry revealed a concomitant loss of MSH2 and MSH6 in the tumor cells, which implicated mutant MSH2 gene. She has remained well with no recurrence for 2.9 years since her surgery. We herein report a case of PDAC with MMR deficiency, resected after long-term observation.

Viral loads correlate with upregulation of PD-L1 and worse patient prognosis in Epstein-Barr Virus-associated gastric carcinoma.

Epstein-Barr virus (EBV)-associated gastric carcinoma (EBVaGC), one of four major gastric cancer types, consists of clonal growth of EBV-infected epithelial cells. However, the significance of viral loads in each tumor cell has not been evaluated. EBV-DNA is stably maintained in episomal form in the nucleus of each cancer cell. To estimate EBV copy number per genome (EBV-CN), qPCR of viral EBNA1 and host GAPDH, standardized by Namalwa DNA (one copy/genome), was applied to the formalin-fixed paraffin embedded (FFPE) surgically resected EBVaGC specimens (n = 43) and EBVaGC cell lines (SNU-719 and NCC-24). In surgical specimens, the cancer cell ratio (CCR) was determined with image analysis, and EBV-CN was obtained by adjusting qPCR value with CCR. Fluorescent in situ hybridization (FISH) was also applied to the FFPE sections using the whole EBV-genome as a probe. In surgical specimens, EBV-CN obtained by qPCR/CCR was between 1.2 and 185 copies with a median of 9.9. EBV-CN of SNU-719 and NCC-24 was 42.0 and 1.1, respectively. A linear correlation was observed with qPCR/CCR data up to 20 copies/genome (40 signals/nucleus), the limit of FISH analysis. In addition, substantial variation in the number of EBV foci was observed. Based on qPCR/CCR, high EBV-CN (>10 copies) correlated with PD-L1 expression in cancer cells (P = 0.015), but not with other pathological indicators. Furthermore, EBVaGC with high EBV-CN showed worse disease-specific survival (P = 0.041). Our findings suggest that cancer cell viral loads may contribute to expression of the immune checkpoint molecule and promotion of cancer progression in EBVaGC.

Increased CXCR3 Expression of Infiltrating Plasma Cells in Hunner Type Interstitial Cystitis.

An up-regulated CXCR3 pathway and affluent plasma cell infiltration are characteristic features of Hunner type interstitial cystitis (HIC). We further examined these two features using bladder biopsy samples taken from 27 patients with HIC and 15 patients with non-IC cystitis as a control. The number of CD3-positive T lymphocytes, CD20-positive B lymphocytes, CD138-positive plasma cells, and CXCR3-positive cells was quantified by digital image analysis. Double-immunofluorescence for CXCR3 and CD138 was used to detect CXCR3 expression in plasma cells. Correlations between CXCR3 positivity and lymphocytic and plasma cell numbers and clinical parameters were explored. The density of CXCR3-positive cells showed no significant differences between HIC and non-IC cystitis specimens. However, distribution of CXCR3-positivity in plasma cells indicated co-localization of CXCR3 with CD138 in HIC specimens, but not in non-IC cystitis specimens. The number of CXCR3-positive cells correlated with plasma cells in HIC specimens alone. Infiltration of CXCR3-positive cells was unrelated to clinical parameters of patients with HIC. These results suggest that infiltration of CXCR3-positive plasma cells is a characteristic feature of HIC. The CXCR3 pathway and specific immune responses may be involved in accumulation/retention of plasma cells and pathophysiology of the HIC bladder.

Tumor Content Chart-Assisted HER2/CEP17 Digital PCR Analysis of Gastric Cancer Biopsy Specimens.

Evaluating HER2 gene amplification is an essential component of therapeutic decision-making for advanced or metastatic gastric cancer. A simple method that is applicable to small, formalin-fixed, paraffin-embedded biopsy specimens is desirable as an adjunct to or as a substitute for currently used HER2 immunohistochemistry and in situ hybridization protocols. In this study, we developed a microfluidics-based digital PCR method for determining HER2 and chromosome 17 centromere (CEP17) copy numbers and estimating tumor content ratio (TCR). The HER2/CEP17 ratio is determined by three variables-TCR and absolute copy numbers of HER2 and CEP17-by examining tumor cells; only the ratio of the latter two can be obtained by digital PCR using the whole specimen without purifying tumor cells. TCR was determined by semi-automatic image analysis. We developed a Tumor Content chart, which is a plane of rectangular coordinates consisting of HER2/CEP17 digital PCR data and TCR that delineates amplified, non-amplified, and equivocal areas. By applying this method, 44 clinical gastric cancer biopsy samples were classified as amplified (n = 13), non-amplified (n = 25), or equivocal (n = 6). By comparison, 11 samples were positive, 11 were negative, and 22 were equivocally immunohistochemistry. Thus, our novel method reduced the number of equivocal samples from 22 to 6, thereby obviating the need for confirmation by fluorescence or dual-probe in situ hybridization to < 30% of cases. Tumor content chart-assisted digital PCR analysis is also applicable to multiple sites in surgically resected tissues. These results indicate that this analysis is a useful alternative to HER2 immunohistochemistry in gastric cancers that can serve as a basis for the automated evaluation of HER2 status.