DDIT3-amplified or low-polysomic pleomorphic sarcomas without MDM2 amplification: Clinicopathological review and immunohistochemical profile of nine cases.

Several high-grade pleomorphic sarcoma cases that cannot be classified into any existing established categories have been reported. These cases were provisionally classified into undifferentiated pleomorphic sarcoma (UPS). Some dedifferentiated liposarcoma (DDLS) cases may also have been classified into the UPS category due to the absence of MDM2 amplification or an atypical lipomatous tumor/well-differentiated liposarcoma component. We retrieved and reviewed 77 high-grade pleomorphic sarcoma cases, initially diagnosed as UPS in 66 cases and DDLS in 11 cases. Fluorescence in situ hybridization (FISH) analyses of DDIT3 and MDM2 were performed for available cases. Of the cases successfully subjected to DDIT3 FISH (n = 56), nine (7 UPS and 2 DDLS) showed DDIT3 amplification but no MDM2 amplification. Two UPS cases showed both telomeric (5') and centromeric (3') amplification of DDIT3 or low polysomy of chromosome 12, whereas 5 UPS and 2 DDLS cases showed 5'-predominant DDIT3 amplification. Histopathologically, all cases showed UPS-like proliferation of atypical pleomorphic tumor cells. Immunohistochemically, only one case showed focal nuclear positivity for DDIT3, supporting the previous finding that DDIT3 expression was not correlated with DDIT3 amplification. All three cases with focal MDM2 expression involved 5'-predominant amplification, two of which showed DDLS-like histological features. The majority of cases (7/9) showed decreased expression in p53 staining, suggesting that DDIT3 amplification regulates the expression of TP53 like MDM2. From a clinicopathological perspective, we hypothesize that DDIT3-amplified sarcoma, especially with 5'-predominant amplification, can be reclassified out of the UPS category.

Clinicopathological findings, prognosis, and Epstein-Barr virus infection in rheumatoid arthritis patients with other iatrogenic immunodeficiency-associated T- and NK-cell lymphoproliferative disorders.

BACKGROUND: Other iatrogenic immunodeficiency-associated (OIIA) T- and natural killer (NK)-cell lymphoproliferative disorders (TNK-LPDs) are rare in patients with rheumatoid arthritis (RA). METHODS: We investigated the clinicopathological characteristics, Epstein-Barr virus (EBV) infection, genetic findings, therapeutic response, and prognostic factors in 21 RA patients with OIIA TNK-LPDs and compared these with those of 39 with OIIA B-cell LPDs (B-LPDs) and 22 with non-OIIA B-LPDs. RESULTS: Immunohistologically, 11 patients (52%) showed CD4+ T-LPDs, and 7 had a T follicular helper (TFH) phenotype. The other nine patients (43%) showed CD8+ T-LPDs, and the remaining one (5%) had features of CD3+ CD4- CD8- nasal type TNK-cell lymphoma. CD30+, p53+, and CMYC+ atypical lymphocytes were identified in seven (33%), eight (38%), and five (24%) patients, respectively. In situ hybridisation detected EBV-encoded RNA (EBER) + large atypical lymphocytes in five patients (24%). Nine of 17 patients (53%) showed clonal peaks of TCRγ by polymerase chain reaction. Withdrawal of MTX and biologic drugs was effective in 12 patients (57%), and 8 (38%) received chemotherapies. Two patients with TFH+ or EBV+ CD4+ CD30+ large cell peripheral T-cell lymphoma, one with CD8+ systemic anaplastic large cell lymphoma, and two with systemic EBV+ CD8+ T-cell lymphoma of childhood showed a lethal progressive clinical course within 13 months. Moreover, > 500 U/L LDH, large atypical lymphocytes, expression of CD30, p53, and CMYC, and EBER+ atypical lymphocytes were significantly poor prognostic factors for overall survival (p < 0.05). Median interval from RA onset to OIIA TNK-LPDs was 72 months, which was shorter than 166 months in OIIA B-LPDs (p = 0.003). EBV+ atypical and reactive lymphocytes were frequently found in 15 patients with OIIA TNK-LPDs (71%), in 27 with OIIA B-LPDs (69%), and only in 3 with non-OIIA B-LPDs (14%). CONCLUSIONS: OIIA TNK-LPDs occurred in early phase of RA, compared with OIIA B-LPDs, and occasionally showed a lethal progressive clinical course. Detection of OIIA TNK-LPD patients with poor prognostic factors is necessary. EBV infection in immunosuppressed patients due to persistent RA, MTX, and biologic drugs may play a role in forming the tumour microenvironment and lymphomagenesis of TNK-LPDs.

Comparative analyses of tumour immune microenvironment between collecting duct carcinoma and fumarate hydratase-deficient renal cell carcinoma.

AIMS: Collecting duct carcinoma (CDC) and fumarate hydratase-deficient renal cell carcinoma (FH-deficient RCC) have similar histological morphologies and both show a poor prognosis. Programmed death ligand 1 (PD-L1) inhibitor has been approved for the treatment of RCC. However, tumour-infiltrating neutrophils stimulated by interleukin-8 (IL-8) interfere with PD-L1 inhibitors. Here, we retrospectively analysed PD-L1 and IL-8 expression, and examined its relationship with infiltrating immune cells. METHODS: Nine cases of CDC and seven cases of FH-deficient RCC were selected. We defined PD-L1 and IL-8 expression by the Tumour Proportion Score and Combined Positive Score (CPS). We counted the numbers of CD8+, CXCR2+, CD11b+, CD66b+ and CD33+ immune cells located in the tumour components. RESULTS: A number of CXCR2+ (p=0.0058), CD11b+ (p=0.0070) and CD66b+ (p=0.0067) immune cells infiltrating into CDC were significantly higher than those infiltrating into FH-deficient RCC. In CDC, PD-L1 expression was correlated with a high density of CD8+ lymphocytes (p=0.0389), but was not in FH-deficient RCC (p=0.6985). IL-8 CPS was significantly higher in CDC than in FH-deficient RCC (p=0.0069). In addition, among the CDC cases, IL-8 CPS showed significant positive correlations with CXCR2+, CD11b+ and CD66b+ immune cell densities (p=0.0250, p=0.0104 and p=0.0374, respectively), whereas FH-deficient RCC showed no significant correlations between IL-8 CPS and immune cell densities. CONCLUSIONS: Our results suggest the difference of each tumour microenvironment between CDC and FH-deficient RCC, and IL-8 is a potential therapeutic target for treating CDC, but not FH-deficient RCC.

Synchronous gallbladder metastasis originating from residual gastric cancer: a case report and the review of literature.

BACKGROUND: Gastric cancer rarely metastasizes to the gallbladder. Furthermore, there has never been a case report of simultaneous gallbladder metastasis from residual gastric cancer. Here, we report a case of synchronous gallbladder metastasis originating from a residual gastric cancer. CASE PRESENTATION: A 67-year-old man underwent a follow-up upper endoscopy 18 months after a partial gastrectomy for gastric cancer; an ulcerative lesion was found in the remnant stomach at the gastrojejunal anastomosis. A biopsy revealed gastric signet-ring cell carcinoma (SRCC). A full-body examination revealed no abnormalities other than gallstones in the gallbladder. With a diagnosis of residual gastric cancer (cT2N0M0 cStage I), the patient underwent open total gastrectomy and cholecystectomy. Macroscopic findings of the resected specimen revealed thickening of the gallbladder wall; however, no obvious neoplastic lesions were found on the mucosal surface of the gallbladder. The pathological findings showed that the SRCC had invaded the submucosa of the gastrojejunostomy site with a high degree of lymphatic invasion and lymph node metastases. SRCCs were also found in the lymphatic vessels of the gallbladder wall. These findings suggested the possibility of gallbladder metastasis through lymphatic vessels. The patient and his family members refused postoperative chemotherapy. Ten months after the operation, the patient experienced respiratory failure due to lymphangitis carcinomatosa and died. CONCLUSIONS: At present, it is difficult to determine whether resection of the gallbladder contributes to an improved prognosis of gastric cancer patients. However, reports in such cases demonstrate that gallbladder metastasis could be a poor predictor of prognosis for gastric cancer.

Approach for reclassification of collecting duct carcinoma and comparative histopathological analysis with SMARCB1/INI1-deficient renal cell carcinoma and fumarate hydratase-deficient renal cell carcinoma.

Collecting duct carcinoma (CDC) is a rare subset of high-grade renal cell carcinoma (RCC). To diagnose CDC, it is necessary to rule out other renal tumors including renal medullary carcinoma and fumarate hydratase (FH)-deficient RCC. However, there is overlap in the morphology of these three tumors, which all have poor outcomes. There is also still a need to sufficiently examine the therapeutic strategies for each of these tumors. In this study, we retrospectively reclassified invasive/infiltrating high-grade RCC and investigated its pathological features. We reviewed 18 cases previously diagnosed as "CDC," "FH-deficient RCC," and "unclassified RCC," which were reclassified as SMARCB1/INI1-deficient RCC, FH-deficient RCC, and CDC by SMARCB1/INI1, FH, and 2SC immunohistochemistry (IHC) and FH gene mutational status. As the result, 18 cases were reclassified into 2 cases of SMARCB1/INI1-deficient RCC, 7 cases of FH-deficient RCC, and 9 cases of CDC. The morphological features of each group overlapped, and no specific immunohistochemical expression except for SMARCB1/INI1, FH, and 2SC was detected. These results suggest that invasive/infiltrating high-grade RCC should be diagnosed by the combination of immunohistochemistry and molecular biological technique.

Novel case of laparoscopically resected gastric adenocarcinoma concurrent with lanthanum deposition.

A 73-year-old man taking lanthanum carbonate for hemodialysis showed progressing gastric mucosal changes with lanthanum deposition. Regular examination revealed concurrent gastric carcinoma. The extent and depth of its invasion were ambiguous because of the surrounding lanthanum deposition. Furthermore, there could be other potent carcinomas, and curative laparoscopic gastrectomy was performed.

Histological background of dedifferentiated solitary fibrous tumour.

AIMS: Dedifferentiation is a histological phenomenon characterised by abrupt transition of histology to a sarcomatous component with high-grade malignant potential in solitary fibrous tumour (SFT). The authors histologically reviewed SFT cases to reveal the histological background of dedifferentiated SFTs. METHODS: Clinicopathological and histopathological findings of 145 SFT cases were reviewed. Immunohistochemical staining and genetic analysis were also performed. RESULTS: The non-dedifferentiated components showed a cellular component in 45 of 145 (31%), high mitotic rate (≥4/10 high-powered field) in 12 of 145 (8.2%) tumours, necrosis in 7 of 145 (4.8%) tumours, multinodular growth pattern in 39 of 132 (29.5%) available tumours and intratumoural fibrous septa in 37 of 131 (28.2%). Immunohistochemically, the non-dedifferentiated components were positive for CD34 in 128 of 141 (90.7%), bcl-2 in 101 of 133 (75.9%), nuclear pattern of ß-catenin in 64 of 127 (50.3%) and p16 in 22 of 140 (15.7%). Loss of Rb protein expression was detected in 17 of 110 (15.4%) cases. Statistically, cellular component, multinodular structure, p16 overexpression and Rb protein loss were significantly associated with dedifferentiation. Moreover, cellular component and multinodular structure were significantly associated with p16 overexpression and Rb protein loss. All the non-deddifferentiated components showed wild type of p53 expression. The dedifferentiated components of all 10 dedifferentiated tumours presented positivity for p16 in 9 of 10 (90%) and mutational type of p53 in 5 of 10 (50%). Loss of Rb protein expression was detected in 6 of 10 (60%). CONCLUSIONS: The authors propose that cellular or multinodular transformation may be associated with dedifferentiation. They also suggest that cellular and multinodular transformation may be associated with p16 overexpression and Rb downregulation.

Programmed cell death-ligand 1 (PD-L1)+ tumour cells and low-reacting programmed cell death 1 (PD1)+ tumour-infiltrating lymphocytes predict poor prognosis in Epstein-Barr virus+ diffuse large B-cell lymphoma.

Epstein-Barr virus (EBV)+ diffuse large B-cell lymphoma (DLBCL) has specific tumour cell characteristics, and these patients have worse outcomes than EBV-negative DLBCL patients. We compared 38 EBV+ DLBCL patients with 43 methotrexate-associated EBV+ B-cell lymphoproliferative disorders (MTX+/EBV+ BLPDs) and 30 non-germinal centre (GC) subtype DLBCL. Lymphoma cells of the EBV+ DLBCL group were positive for BCL2 in 17 patients (44.7%), CMYC in 23 patients (60.5%), and p53 in 33 patients (86.8%), which was significantly higher than in the MTX+/EBV+ BLPD group (P < 0.05), and were positive for CD30 in 29 patients (76.3%), compared with two in non-GC subtype DLBCL (6.7%) (P < 0.0001). Significantly more EBV+ DLBCL patients (n = 16, 42.1%) had programmed cell death-ligand 1 (PD-L1)+ tumour cells than patients with non-GC subtype DLBCL (n = 5, 16.7%; P = 0.024), and PD-L1+ tumour cells were more common in advanced stages than in early stages (P = 0.048). Twenty-five EBV+ DLBCL patients (69.4%) had few reactive PD1+ tumour-infiltrating lymphocytes (TILs), compared with 12 patients with MTX+/EBV+ BLPDs (37.5%) (P = 0.008). In the EBV+ DLBCL group, CD30, BCL2, CMYC, and p53 expression was not related to patient prognosis. Poor outcomes were associated with PD-L1+ tumour cells (P = 0.001) and low-reacting PD1+ TILs (P = 0.02), while their combination conferred a worse outcome (P < 0.0001). Immune evasion by PD-L1+ tumour cells and exhaustion of PD1+ TILs may occur in EBV+ DLBCL patients, and PD-L1/PD1 interactions may influence tumour progression and poor prognosis.

Role of barium enema examination for the diagnosis of submucosal invasion depth in T1 colorectal cancers.

BACKGROUND: The indication for endoscopic resection for submucosally invasive colorectal cancer (T1-CRC) depends on the preoperative diagnosis of invasion depth. The aim of this investigation was to evaluate the association between barium enema examination (BE) profile views and depth of submucosal (SM) invasion in CRCs. METHODS: We reviewed the radiographic and endoscopic findings of 145 T1-CRCs diagnosed from 2008 to 2019. We measured the widths of horizontal and vertical rigidity under a BE profile view corresponding to CRC and compared the values with SM invasion depth. Horizontal rigidity was defined as the horizontal length and vertical rigidity as the vertical width of the barium defect corresponding to each target lesion. The most appropriate cut-off values for predicting SM invasion ≥1.8 mm were calculated by receiver operating characteristic curve analysis. RESULTS: Values of horizontal rigidity (r = 0.626, P < 0.05) and vertical rigidity (r = 0.482, P < 0.05) correlated significantly with SM invasion depth. The most appropriate cut-off values for the prediction of SM invasion depth ≥ 1.8 mm were 4.5 mm for horizontal rigidity, with an accuracy of 80.7%; and 0.7 mm for vertical rigidity, with an accuracy of 77.9%. The prevalence of lympho-vascular invasion was significantly different when those cut-off values were applied (43.2% vs. 17.5% for horizontal rigidity, P < 0.005). CONCLUSIONS: In T1-CRC, values of horizontal and vertical rigidities under a BE profile view were correlated with SM invasion depth. While the accuracy of the rigidities for the prediction of SM invasion depth ≥ 1.8 mm was not high, horizontal rigidity may be predictive of lympho-vascular invasion, thus aiding in therapeutic decision-making.

Large cell morphology, CMYC+ tumour cells, and PD-1+ tumour cell/intense PD-L1+ cell reactions are important prognostic factors in nodal peripheral T-cell lymphomas with T follicular helper markers.

BACKGROUND: The clinicopathological characteristics and prognostic factors in nodal peripheral T-cell lymphomas (PTCLs) with two or more T follicular helper markers (TFH+) are not adequately investigated. METHODS: Immunohistologically, we selected 22 patients with TFH+ lymphoma (PTCL-TFH) in 47 of PTCL-not otherwise specified (NOS), and subclassified into large and small cell groups. We compared the two groups with 39 angioimmunoblastic T-cell lymphoma (AITL) and seven follicular T-cell lymphoma (F-TCL) patients. Prognostic factors were analysed by overall survival in patients with three types of TFH+ PTCLs. RESULTS: Thirteen large cell and nine small cell PTCL-TFH patients had more than two TFH markers including programmed cell death-1 (PD-1). Large cell PTCL-TFH showed frequent CMYC expression in 10 patients (77%), and four of 11 large cell group (36%) had somatic RHOA G17V gene mutation by Sanger sequencing. Large cell PTCL-TFH patients showed significantly worse prognosis than those of the small cell group, AITL, and F-TCL (p < 0.05). In TFH+ PTCLs, CMYC+ tumour cells, and combined PD-1 ligand 1 (PD-L1) + tumour cells and intense reaction of PD-L1+ non-neoplastic cells (high PD-L1+ cell group) were significantly poor prognostic factors (p < 0.05). Combinations of CMYC+ or PD-1+ tumour cells and high PD-L1+ cell group indicated significantly poor prognosis (p < 0.01). CONCLUSION: Large cell PTCL-TFH indicated poor prognosis in TFH+ PTCLs. These data suggested that CMYC+ tumour cells and intense PD-L1+ cell reaction influenced tumour cell progression in TFH+ PTCLs, and PD-1+ tumour cell/intense PD-L1+ cell reactions may play a role in immune evasion.

Recurrent intraductal papillary neoplasm of the bile duct due to intraductal dissemination: a case report and literature review.

BACKGROUND: Intraductal papillary neoplasm of the bile duct (IPNB) is a subtype of biliary tumor. The 5-year survival rate of patients with IPNB who underwent curative resection is 81%. However, IPNB is known to often recur in other parts of the bile duct. Nevertheless, its mechanism remains poorly understood. Herein, we report the case of a patient with recurrent IPNB, which was considered to be attributed to intraductal dissemination in the common bile duct at 12 months after curative resection. We also made a review of the existing literature. CASE PRESENTATION: A 69-year-old man was referred to our hospital for the evaluation and dilation of an intrahepatic bile duct (IHBD) mass. Computed tomography (CT) findings confirmed a mass in the left hepatic duct. Left trisectionectomy, extrahepatic bile duct resection with biliary reconstruction, and regional lymph node dissection were performed. Intraoperative examination of the resection margin at the common bile duct and posterior segmental branch of the hepatic duct was negative for the presence of malignant cells. Histologically, the tumor showed intraductal papillary growth of the mucinous epithelium and was diagnosed as non-invasive IPNB. It had a papillary structure with atypical epithelial cells lined up along the neoplastic fibrovascular stalks. Immunohistochemically, this was as a gastric-type lesion. At 12 postoperative months, CT revealed a 1.5-cm mass in the lower remnant common bile duct. We performed subtotal stomach-preserving pancreaticoduodenectomy. The tumor exhibited papillary growth and was microscopically and immunohistochemically similar to the first tumor. At approximately 16 months after the patient's second discharge, CT showed an abdominal mass at the superior mesenteric plexus, which was diagnosed as recurrent IPNB. Chemotherapy is ongoing, and the patient is still alive. In this case, as described in many previous reports, IPNB recurred below the primary lesion in the bile duct. CONCLUSION: Based on our review of previous reports on IPNB recurrence, intraductal dissemination was considered one of the mechanisms underlying recurrence after multicentric development. Considering the high frequency and oncological conversion of recurrence in IPNB, regular follow-up examination is essential to achieve better prognosis in patients with recurrent IPNB.

Gastric epithelial neoplasm of fundic-gland mucosa lineage: proposal for a new classification in association with gastric adenocarcinoma of fundic-gland type.

BACKGROUND: Gastric adenocarcinoma of fundic-gland type (GA-FG) is a rare variant of gastric neoplasia. However, the etiology, classification, and clinicopathological features of gastric epithelial neoplasm of fundic-gland mucosa lineage (GEN-FGML; generic term of GA-FG related neoplasm) are not fully elucidated. We performed a large, multicenter, retrospective study to establish a new classification and clarify the clinicopathological features of GEN-FGML. METHODS: One hundred GEN-FGML lesions in 94 patients were collected from 35 institutions between 2008 and 2019. We designed a new histopathological classification of GEN-FGML using immunohistochemical analysis and analyzed via clinicopathological, immunohistochemical, and genetic evaluation. RESULTS: GEN-FGML was classified into 3 major types; oxyntic gland adenoma (OGA), GA-FG, and gastric adenocarcinoma of fundic-gland mucosa type (GA-FGM). In addition, GA-FGM was classified into 3 subtypes; Type 1 (organized with exposure type), Type 2 (disorganized with exposure type), and Type 3 (disorganized with non-exposure type). OGA and GA-FG demonstrated low-grade epithelial neoplasm, and GA-FGM should be categorized as an aggressive variant of GEN-FGML that demonstrated high-grade epithelial neoplasm (Type 2 > 1, 3). The frequent presence of GNAS mutation was a characteristic genetic feature of GEN-FGML (7/34, 20.6%; OGA 1/3, 33.3%; GA-FG 3/24, 12.5%; GA-FGM 3/7, 42.9%) in mutation analysis using next-generation sequencing. CONCLUSIONS: We have established a new histopathological classification of GEN-FGML and propose a new lineage of gastric epithelial neoplasm that harbors recurrent GNAS mutation. This classification will be useful to estimate the malignant potential of GEN-FGML and establish an appropriate standard therapeutic approach.

Clinicopathological findings of systemic Epstein-Barr virus-positive T-lymphoproliferative diseases in younger and older adults.

BACKGROUND: Systemic Epstein-Barr virus+ T-cell lymphoma (sEBV+ TCL) occurs in childhood and young adults, and is exceptionally rare in older adults. METHODS: We investigated clinicopathological features in 16 patients of various ages with systemic EBV+ CD8+ T-lymphoproliferative diseases. RESULTS: Eight younger patients and four of eight older adults had sEBV+ CD8+ TCL, with invasion by medium-sized to/or large atypical lymphocytes primarily in bone marrow and lymph nodes, hemophagocytic lymphohistiocytosis (HLH), and progressive clinicopathological course. A further two patients demonstrated EBV+ node-based CD8+ large TCL without HLH, while the remaining two had the systemic form of chronic active EBV infection (sCAEBV) with CD8+ small lymphocytes. Past history of sCAEBV-like lesions was observed in one sEBV+ TCL patient (8.3%). Immunohistologically, in 12 sEBV+ TCL patients, atypical lymphocytes were positive for phosphate signal transducer and activator of transcription 3 (66.7%), CMYC (83.3%), and p53 (75%). Strong reactions of programmed cell death-ligand (PD-L)1+ tumor or non-neoplastic cells were detected in nine sEBV+ TCL patients (75%). Clonal peaks of the T-cell receptor (TCR) γ gene were detected in eight sEBV+ TCL patients by polymerase chain reaction. Four younger patients in sEBV+ TCL (33.3%) are in remission with chemotherapies including etoposide, and three of the four underwent allogeneic stem cell transplantation (SCT). CONCLUSION: sEBV+ CD8+ TCL was observed in younger and older adults with less history of sCAEBV. HLH, tumor cell atypia, immunohistological findings, and progressive clinical course were characteristic of sEBV+ CD8+ TCL. Prompt chemotherapy and SCT induced tumor regression in sEBV+ CD8+ TCL patients.

Pancreatic enzymatic mediastinitis followed by total gastrectomy with splenectomy: report of two cases.

BACKGROUND: Acute mediastinitis is a rare disease that rapidly progresses with a high mortality rate. Its most common cause is direct injury of the mediastinum, including iatrogenic causes such as cardiac surgery or upper endoscopy. Enzymatic mediastinitis is a rare complication of a pancreatic fistula caused by the inflammatory digestion of the parietal peritoneum spreading to the mediastinum. Here, we present two cases of enzymatic mediastinitis caused by total gastrectomy with splenectomy. One of them was successfully treated and cured after early diagnosis and transabdominal drainage. CASE PRESENTATION: Case 1 was that of a 60-year-old man (body mass index [BMI] 27) with a medical history of diabetes and hypertension who was diagnosed with advanced gastric cancer in the upper body of the stomach. A total gastrectomy with splenectomy was performed. The patient experienced acute respiratory failure 24 h after surgery. Pulmonary embolism was suspected, so a computed tomography (CT) scan was performed; however, no relevant causes were found. Although he was immediately intubated and treated with catecholamine, he died in the intensive care unit (ICU) 40 h after surgery. Post-mortem findings revealed retroperitonitis caused by a pancreatic fistula spreading towards the mediastinum, causing severe mediastinitis; a review of the CT scan revealed pneumomediastinum. We concluded that the cause of death was enzymatic mediastinitis due to post-gastrectomy pancreatic fistula. Case 2 involved a 61-year-old man (BMI 25) with a medical history of appendicitis who was diagnosed with advanced gastric cancer at the gastric angle between the lesser curvature and the pylorus, spreading to the upper body of the stomach. A total gastrectomy with splenectomy was also performed. The patient had a high fever 3 days after the surgery, and a CT scan revealed pneumomediastinum, indicating mediastinitis. As the inflammation was below the bronchial bifurcation, we chose a transabdominal approach for drainage. The patient was successfully treated and discharged. CONCLUSION: Acute mediastinitis caused by gastrectomy is rare. The acknowledgment of abdominal surgery as a cause of mediastinitis is important. In treating mediastinitis caused by abdominal surgery, transabdominal drainage may be a minimally invasive yet effective method if the inflammation is mainly located below the bifurcation of the trachea.

Myxoepithelioid tumour with chordoid features: a clinicopathological, immunohistochemical and genetic study of 14 cases of SMARCB1/INI1-deficient soft-tissue neoplasm.

AIMS: Complete loss of SMARCB1/INI1 in soft-tissue tumours such as malignant rhabdoid tumour, epithelioid sarcoma, myoepithelial tumour of soft tissue and extraskeletal myxoid chondrosarcoma is often associated with high-grade malignancy and poor prognosis. The diagnosis is sometimes challenging, owing to histological similarities, so careful differential diagnosis is required. Therefore, soft-tissue tumours with complete SMARCB1/INI1 loss could potentially include an unknown entity. METHODS AND RESULTS: We analysed 160 cases of SMARCB1/INI1-deficient soft-tissue tumour, and found 14 cases that were not classifiable into already existing categories and had common clinical and histological features. These involved two male and 12 female patients, ranging in age from 20 years to 61 years. The tumours were located in the the puboinguinal region (n = 13) and pelvic cavity (n = 1). Histologically, the tumours showed relatively uniform epithelioid to spindle-shaped cells with myxoid stroma. All tumours showed immunoreactivity for brachyury, epithelial membrane antigen, and progesterone receptor, and 12 of 14 cases did so for oestrogen receptor. Variable positive staining for α-smooth muscle actin, S100 and glial fibrillary acidic protein (GFAP) was seen. NR4A3 and EWSR1 gene rearrangements were not detected in 13 and 11 examined cases, respectively. Clinical follow-up data for the 14 patients showed that 13 were alive without disease and one had been lost to follow-up; four patients developed local recurrence and/or metastases. CONCLUSION: The designation 'myxoepithelioid tumour with choroid features' (METC) was proposed as a tumour with intermediate malignancy controllable with appropriate treatment, including the entity of myoepithelioma-like tumour of the vulvar region. METC represents a novel and independent subset that is histologically, biologically and clinically distinct from already existing SMARCB1/INI1-deficient soft-tissue tumours.

Outcomes of methotrexate-associated lymphoproliferative disorders in rheumatoid arthritis patients treated with disease-modifying anti-rheumatic drugs.

Recently, the use of targeted synthetic or biological disease-modifying anti-rheumatic drugs (ts/bDMARDs) in addition to conventional synthetic (cs)DMARDs including methotrexate (MTX) for rheumatoid arthritis (RA) has increased. However, whether ts/bDMARDs are associated with the development and clinicopathological features of MTX-associated lymphoproliferative disorder (MTX-LPD) in patients with RA remains unknown. Therefore, we evaluated the clinical outcomes of 121 patients with MTX-LPD. Results showed that prior use of ts/bDMARDs was not associated with the different histopathological subtypes of MTX-LPD. Patients with polymorphic-type LPD had a better event-free survival than those with diffuse large B-cell lymphoma (DLBCL), classical Hodgkin lymphoma and peripheral T-cell lymphoma. The pathological subtype of lymphoma could predict the clinical outcome of MTX-LPD. In patients with DLBCL, the use of tumour necrosis factor-alpha (TNF-α) inhibitors prior to MTX-LPD onset was associated with a higher non-relapse mortality. Further, patients with RA previously treated with Janus kinase (JAK) inhibitors more commonly required chemotherapy than those treated with csDMARDs alone, indicating disease aggressiveness. Hence, special caution should be observed when managing patients with MTX-LPD previously treated with JAK or TNF-α inhibitors for RA.

Morphological, immunohistochemical, and genomic analyses of papillary renal neoplasm with reverse polarity.

Papillary renal neoplasm with reverse polarity (PRNRP) is a recently proposed entity of renal tumor. It shows a far better prognosis than papillary renal cell carcinoma (PRCC) and frequently has KRAS missense mutation. In this study, we compared 14 cases of PRNRP and 10 cases of PRCC type 1 (PRCC1) and type 2 (PRCC2) from clinical, morphological, immunohistochemical, and molecular biological perspectives. We subjected all PRNRP and PRCC cases to immunohistochemical analysis. Whole-exome sequencing using next-generation sequencing (NGS) was performed for six cases of PRNRP, three cases of PRCC1, and four cases of PRCC2. A search for KRAS gene mutation in the remaining eight cases of PRNRP was performed by polymerase chain reaction (PCR) sequencing. The results showed that all cases of PRNRP were pT1N0M0, none of which followed a course of recurrence or tumor-related death. Immunohistochemical analysis revealed diffuse staining of CK7, EMA, PAX8, and GATA3 but weak or negative staining of CD10, CD15, and AMACR in PRNRP. By NGS and PCR, KRAS missense mutation was detected in 11 of 14 PRNRP cases, although pathogenic KRAS mutation was not observed in PRCC1 and PRCC2. NGS analysis revealed less tumor mutation burden in PRNRP than in PRCC. PRNRP also showed no specific chromosomal copy number abnormalities, including gains of 7 and 17. In conclusion, we propose that PRNRP is a distinct condition from PRCC.

Endoscopic and clinicopathological characteristics of colorectal T/NK cell lymphoma.

BACKGROUND: Colorectal T/natural killer (NK)-cell lymphomas (TNKCL) are very rare. Endoscopic and clinicopathological characteristics of colorectal TNKCL have not been clearly demonstrated. In this study, we demonstrated the clinical characteristics of colorectal TNKCL. METHODS: Endoscopic and clinicopathological characteristics were investigated in 27 patients with colorectal monomorphic epitheliotropic intestinal T-cell lymphoma (MEITL), adult T-cell leukemia/lymphoma (ATLL), and other types of TNKCL. RESULTS: Nine TNKCL patients (33%) were classified as MEITL, 11 (41%) as ATLL, and seven (26%) as other. Four patients with Epstein-Barr Virus-positive (EBV+) TNKCL, two indolent T-cell lymphoproliferative disorder and one anaplastic large cell lymphoma were included in the other group. Endoscopically, six MEITL (67%) and five ATLL (46%) showed diffuse-infiltrating type, in which the main endoscopic lesion was edematous mucosa in MEITL, while aphthoid erosion and edematous mucosa were typical in ATLL. Ulcerative type was identified in four other group patients (57%), including two EBV+ TNKCL. An increase in atypical T-intraepithelial lymphocytes (T-IELs) was noted in seven MEITL (88%) and six ATLL (60%) patients, but not in the other group (0%) patients. Five MEITL patients (56%) showed features of lymphocytic proctocolitis with increased CD8+ T-IELs. CONCLUSIONS: MEITL and ATLL occasionally invaded the colorectum, and primary involving MEITL was observed. Diffuse infiltrating type was the characteristic endoscopic finding in colorectal MEITL and ATLL, while ulcerative type was observed in the other group. Features of lymphocytic proctocolitis may be prodromal findings of MEITL.

Automated assessment of Ki-67 in breast cancer: the utility of digital image analysis using virtual triple staining and whole slide imaging.

AIMS: Precise evaluation of proliferative activity is essential for the stratified treatment of luminal-type breast cancer (BC). Immunohistochemical staining of Ki-67 has been widely used to determine proliferative activity and is recognised to be a useful prognostic marker. However, there remains discussion concerning the methodology. We aimed to develop an automated and reliable Ki-67 assessment approach for invasive BC. MATERIALS AND RESULTS: A retrospective study was designed to include two cohorts consisting of 152 and 261 consecutive patients with luminal-type BC. Representative tissue blocks following surgery were collected, and three serial sections were stained automatically with Ki-67, pan-cytokeratin and p63. The whole slides were scanned digitally and aligned using VirtualTripleStaining - an extension to the VirtualDoubleStaining™ technique provided by Visiopharm software. The aligned files underwent automated invasive cancer detection, hot-spot identification and Ki-67 counting. The automated scores showed a significant positive correlation with the pathologists' scores (r = 0.82, P < 0.0001). Among selected patients with curative surgery and standard adjuvant therapies (n = 130), the digitally assessed low Ki-67 group (<20%) demonstrated a significantly better prognosis (breast cancer-specific survival, P = 0.030; hazard ratio = 0.038) than the high Ki-67 group. CONCLUSIONS: Digital image analysis yielded similar results to the scores determined by experienced pathologists. The prognostic utility was verified in our cohort, and an automated process is expected to have high reproducibility. Although some pitfalls were confirmed and thus need to be monitored by laboratory staff, the application could be utilised for the assessment of BC.

Branch-type intraductal papillary neoplasm of the bile duct treated with laparoscopic anatomical resection: a case report.

BACKGROUND: Intraductal papillary neoplasm of the bile duct (IPNB) is characterized by an intraluminal, growing papillary tumor covered by neoplastic biliary epithelial cells with a fine fibrovascular core. IPNB was introduced as a precancerous and early neoplastic lesion in the 2010 World Health Organization classification of tumors of the digestive system. IPNB eventually invades the bile duct wall and progresses to invasive cholangiocarcinoma. IPNB resembles intraductal papillary mucinous neoplasm of the pancreas (IPMN), particularly the main pancreatic duct type. IPNB cases, possibly corresponding to branch-type IPMN, have been recently reported, and these cases involved the peribiliary glands significantly and showed gross cystic dilatation. Small branch-type intrahepatic IPNB often mimics simple liver cysts, making the diagnosis of IPNB difficult. Some literature recommended surgical resection for treatment. Laparoscopic resection is a good treatment option for small tumor. We herein present the case of branch-type IPNB that was treated with laparoscopic anatomical liver resection 5 years after being detected. CASE PRESENTATION: A 64-year-old woman was undergoing follow-up for primary aldosteronism. In 2012, follow-up computed tomography (CT) incidentally revealed a 7-mm cystic lesion in segment 8 of the liver. From 2012 to 2017, the cystic lesion kept increasing in size, reaching 17 mm. In 2017, CT also revealed a 13-mm mural nodule in the cyst wall. Therefore, the patient was referred to our department for possible malignancy. We suspected a branch-type IPNB; however, the mass was small and diagnosis could not be made without performing biopsy. Accordingly, surgical resection was performed for diagnosis and treatment. Because branch-type IPNB might show horizontal spread through the intrahepatic bile duct, we believed that anatomical resection of the liver was appropriate considering the malignant potential of the lesion. Therefore, laparoscopic anatomical resection of segment 8 of the liver was performed. The resected tumor measured 17 mm and was histologically diagnosed as a high-grade IPNB. CONCLUSION: Branch-type IPNBs are rare but can potentially lead to malignant tumors. Surgical resection is the treatment of choice, with laparoscopic anatomical resection being a good treatment option for this small tumor.