Purpose: Pulmonary tumor thrombotic microangiopathy (PTTM) is a fatal complication of gastric cancer (GC). This study aimed to evaluate the clinical characteristics, outcomes, and immunohistochemical profiles of patients with GC-induced PTTM. Materials and Methods: From 2011 to 2023, 8 patients were clinically diagnosed with PTTM associated with GC antemortem. Clinical features and outcomes were reviewed, and immunohistochemical staining for c-erbB-2, MutL protein homolog 1, and programmed cell death ligand-1 was performed. Results: The median patient age was 56 years (range, 34–66 years). In all the patients, the tumors exhibited either ulceroinfiltrative or diffusely infiltrative gross morphology.The median tumor size was 5.8 cm (range, 2.0 cm–15.0 cm). Poorly differentiated adenocarcinoma was the most common histological type (6/8, 75%), followed by signet ring cell carcinoma (1/8, 12.5%) and moderately differentiated adenocarcinoma (1/8, 12.5%).Chest computed tomography revealed ground-glass opacities (7/8, 87.5%) or tree-in-bud signs (2/8, 25.0%) without definite evidence of pulmonary thromboembolism. Disseminated intravascular coagulation was present in 62.5% (5/8) of the patients diagnosed with PTTM.C-erbB-2 was positive in one patient (1/8, 12.5%). One patient who received palliative chemotherapy after developing PTTM survived for 35 days, whereas the other 7 patients who did not receive chemotherapy after developing PTTM survived for 7 days or less after PTTM diagnosis. Conclusions Most patients with GC-induced PTTM had an undifferentiated-type histology, infiltrative morphology, and extremely poor survival. Palliative chemotherapy may benefit patients with GC-induced PTTM; however, further studies are needed to explore the potential of targeted therapy in these patients.

Purpose: Pulmonary tumor thrombotic microangiopathy (PTTM) is a fatal complication of gastric cancer (GC). This study aimed to evaluate the clinical characteristics, outcomes, and immunohistochemical profiles of patients with GC-induced PTTM. Materials and Methods: From 2011 to 2023, 8 patients were clinically diagnosed with PTTM associated with GC antemortem. Clinical features and outcomes were reviewed, and immunohistochemical staining for c-erbB-2, MutL protein homolog 1, and programmed cell death ligand-1 was performed. Results: The median patient age was 56 years (range, 34–66 years). In all the patients, the tumors exhibited either ulceroinfiltrative or diffusely infiltrative gross morphology.The median tumor size was 5.8 cm (range, 2.0 cm–15.0 cm). Poorly differentiated adenocarcinoma was the most common histological type (6/8, 75%), followed by signet ring cell carcinoma (1/8, 12.5%) and moderately differentiated adenocarcinoma (1/8, 12.5%).Chest computed tomography revealed ground-glass opacities (7/8, 87.5%) or tree-in-bud signs (2/8, 25.0%) without definite evidence of pulmonary thromboembolism. Disseminated intravascular coagulation was present in 62.5% (5/8) of the patients diagnosed with PTTM.C-erbB-2 was positive in one patient (1/8, 12.5%). One patient who received palliative chemotherapy after developing PTTM survived for 35 days, whereas the other 7 patients who did not receive chemotherapy after developing PTTM survived for 7 days or less after PTTM diagnosis. Conclusions Most patients with GC-induced PTTM had an undifferentiated-type histology, infiltrative morphology, and extremely poor survival. Palliative chemotherapy may benefit patients with GC-induced PTTM; however, further studies are needed to explore the potential of targeted therapy in these patients.

Purpose: Pulmonary tumor thrombotic microangiopathy (PTTM) is a fatal complication of gastric cancer (GC). This study aimed to evaluate the clinical characteristics, outcomes, and immunohistochemical profiles of patients with GC-induced PTTM. Materials and Methods: From 2011 to 2023, 8 patients were clinically diagnosed with PTTM associated with GC antemortem. Clinical features and outcomes were reviewed, and immunohistochemical staining for c-erbB-2, MutL protein homolog 1, and programmed cell death ligand-1 was performed. Results: The median patient age was 56 years (range, 34–66 years). In all the patients, the tumors exhibited either ulceroinfiltrative or diffusely infiltrative gross morphology.The median tumor size was 5.8 cm (range, 2.0 cm–15.0 cm). Poorly differentiated adenocarcinoma was the most common histological type (6/8, 75%), followed by signet ring cell carcinoma (1/8, 12.5%) and moderately differentiated adenocarcinoma (1/8, 12.5%).Chest computed tomography revealed ground-glass opacities (7/8, 87.5%) or tree-in-bud signs (2/8, 25.0%) without definite evidence of pulmonary thromboembolism. Disseminated intravascular coagulation was present in 62.5% (5/8) of the patients diagnosed with PTTM.C-erbB-2 was positive in one patient (1/8, 12.5%). One patient who received palliative chemotherapy after developing PTTM survived for 35 days, whereas the other 7 patients who did not receive chemotherapy after developing PTTM survived for 7 days or less after PTTM diagnosis. Conclusions Most patients with GC-induced PTTM had an undifferentiated-type histology, infiltrative morphology, and extremely poor survival. Palliative chemotherapy may benefit patients with GC-induced PTTM; however, further studies are needed to explore the potential of targeted therapy in these patients.

Purpose: Although partial mesorectal excision (PME) and total mesorectal excision (TME) is primarily indicated for the upper and lower rectal cancer, respectively, few studies have evaluated whether PME or TME is more optimal for middle rectal cancer. Methods: This study included 671 patients with middle and upper rectal cancer who underwent robot-assisted PME or TME. The 2 groups were optimized by propensity score matching of sex, age, clinical stage, tumor location, and neoadjuvant treatment. Results: Complete mesorectal excision was achieved in 617 of 671 patients (92.0%), without showing a difference between the PME and TME groups. Local recurrence rate (5.3% vs. 4.3%, P>0.999) and systemic recurrence rate (8.5% vs. 16.0%, P=0.181) also did not differ between the 2 groups, in patients with middle and upper rectal cancer. The 5-year disease-free survival (81.4% vs. 74.0%, P=0.537) and overall survival (88.0% vs. 81.1%, P=0.847) also did not differ between the PME and TME groups, confined to middle rectal cancer. Moreover, 5-year recurrence and survival rates were not affected by distal resection margins of 2 cm (P=0.112) to 4 cm (P>0.999), regardless of pathological stages. Postoperative complication rate was higher in the TME than in the PME group (21.4% vs. 14.5%, P=0.027). Incontinence was independently associated with TME (odds ratio [OR], 2.009; 95% confidence interval, 1.015–3.975; P=0.045), along with older age (OR, 4.366, P<0.001) and prolonged operation time (OR, 2.196; P=0.500). Conclusion PME can be primarily recommended for patients with middle rectal cancer with lower margin of >5 cm from the anal verge.

Background/Aims: Delayed perforation is a rare but serious adverse event of gastric endoscopic submucosal dissection (ESD). The aim of this study was to clarify the clinical features and appropriate management strategy of patients with delayed perforation. Methods: Among 11,531 patients who underwent gastric ESD, the clinical features and outcomes of patients who experienced delayed perforation were retrospectively reviewed and compared with those of the control group. Results: Delayed perforation occurred in 15 of 11,531 patients (0.13%). The patients with delayed perforation were significantly older than those without delayed perforation (p=0.027). The median time to diagnosis of delayed perforation was 28.8 hours (range, 14 to 71 hours). All 15 patients with delayed perforation complained of severe abdominal pain after gastric ESD and underwent subsequent chest X-rays (CXRs) for evaluation. In subsequent CXR, free air was found in 12 patients (80%). For three (20%) patients without free air in CXR, delayed perforation was finally diagnosed by computed tomography. Leukocytosis was significantly less frequent in the patients without free air in CXR (p=0.022). A perforation hole smaller than 1 cm in size was more frequently observed in the six patients who underwent successful non-surgical treatments than in the nine patients who underwent surgery (p<0.001). There was no mortality related to delayed perforation. Conclusions One-fifth of the patients with delayed perforation did not show free air in CXR and exhibited less leukocytosis than those with free air. Non-surgical treatments including endoscopic closure might be considered as an initial treatment modality for delayed perforation smaller than 1 cm.

Background/Aims: Lymphoepithelioma-like carcinoma (LELC) is a rare subtype of gastric cancer. We aimed to identify the clinicopathological features and rate of lymph node metastasis (LNM) to investigate the feasibility of endoscopic submucosal dissection for early gastric LELC confined to the mucosa or submucosa. Methods: We compared the clinicopathological characteristics of 116 early gastric LELC patients and 5,753 early gastric well- or moderately differentiated (WD or MD) tubular adenocarcinoma patients treated by gastrectomy. Results: Compared to WD or MD early gastric cancer (EGC) patients, early LELC patients were younger and had a higher prevalence of proximally located tumors. Despite more frequent deep submucosal invasion (86.2% vs 29.8%), lymphatic invasion was less frequent (6.0% vs 16.2%) in early LELC patients than in WD or MD EGC patients. Among tumors with deep submucosal invasion, the tumor size was smaller, lymphatic invasion was less frequent (6.0% vs 40.2%) and the rate of LNM was lower (10.0% vs 19.4%) in patients with LELC than in those with WD or MD EGC. The overall rate of LNM in early LELC patients was 8.6% (10/116). The risk of LNM in patients with mucosal, shallow submucosal invasive, or deep submucosal invasive LELC was 0% (0/6), 0% (0/10), and 10% (10/100), respectively. Conclusions Early LELC is a distinct subtype of EGC with more frequent deep submucosal invasion but less lymphatic invasion and LNM than WD or MD EGCs. Endoscopic submucosal dissection may be considered curative for patients with early LELC confined to the mucosa or shallow submucosa, given its negligible rate of LNM.

Purpose: Foveolar-type adenocarcinoma of the stomach is a rare variant of gastric cancer.The clinicopathological features and outcomes of endoscopic submucosal dissection (ESD) for gastric foveolar-type adenocarcinoma remain unclear. Materials and Methods: This study included 1,161 patients who underwent ESD for single early gastric cancers (EGCs) (78 foveolar-type adenocarcinomas and 1,083 well-differentiated [WD] adenocarcinomas). The clinicopathological features and short- and long-term outcomes of ESD for gastric foveolar-type adenocarcinomas were reviewed and compared with those for WD EGCs. Results: Gastric foveolar-type adenocarcinomas were larger and more likely to exhibit an elevated macroscopic appearance than WD EGCs. Foveolar-type adenocarcinomas exhibited higher rates of lymphatic invasion, histological heterogeneity, and lateral margin involvement than WD EGCs. The en bloc R0 and curative resection rates of foveolar-type adenocarcinoma were 85.9% and 76.9%, respectively. Both foveolar-type adenocarcinoma rates were significantly lower than those of WD EGCs (95.8% and 91.3%, respectively). Lateral margin involvement accounted for 55.6% of the non-curative resection cases of foveolar-type adenocarcinoma.Among patients who underwent curative ESD for foveolar-type adenocarcinoma, no recurrence occurred during the median 62.3 months of follow-up. No lymph node metastases were detected in patients with foveolar-type adenocarcinoma who underwent additional surgery following ESD. The overall and disease-specific survival rates of patients with foveolar-type adenocarcinoma were comparable to those of patients with WD EGC. Conclusions Gastric foveolar-type adenocarcinomas have distinct clinicopathological features among WD EGCs. Given favorable long-term outcomes after curative resection, ESD can be indicated for early gastric foveolar-type adenocarcinomas.

Objectives: Localized gastric Langerhans cell histiocytosis (LCH) characterized by abnormal proliferation of Langerhans cells in the stomach without systemic involvement, is rare; therefore, the clinical characteristics and outcomes of LCH remain unclear. We investigated the clinical characteristics and outcomes in patients diagnosed with localized gastric LCH and have also discussed treatment strategies for this rare disease. Methods: The study included seven patients diagnosed with localized gastric LCH at our hospital between September 1997 and December 2023. We retrospectively reviewed medical records and analyzed the clinicopathological characteristics and patient outcomes. Results: Endoscopically, localized gastric LCH appeared as a small erosion in the distal part of the stomach. Positron emission tomography-computed tomography revealed normal findings in 100.0% (4/4) of patients during pre-treatment workup. Immunohistochemical analysis using S-100 and CD1a showed immunopositive cells in all tested patients. Of the six patients who underwent follow-up, two (33.3%) showed metachronous recurrence at a location distinct from the initial site. However, all patients eventually showed spontaneous regression of the disease, and no gastric LCH-induced mortality was observed during follow-up. Conclusions Careful and regular surveillance may be sufficient for patients with localized gastric LCH without systemic involvement.

Purpose: This study was designed to determine the feasibility of preoperative chemoradiotherapy (PCRT) in patients with clinical T2N0 distal rectal cancer. Methods: Patients who underwent surgery for clinical T2N0 distal rectal cancer between January 2008 and December 2016 were included. Patients were divided into PCRT and non-PCRT groups. Non-PCRT patients underwent radical resection or local excision (LE) according to the surgeon’s decision, and PCRT patients underwent surgery according to the response to PCRT. Patients received 50.0 to 50.4 gray of preoperative radiotherapy with concurrent chemotherapy. Results: Of 127 patients enrolled, 46 underwent PCRT and 81 did not. The mean distance of lesions from the anal verge was lower in the PCRT group (P=0.004). The most frequent operation was transanal excision and ultralow anterior resection in the PCRT and non-PCRT groups, respectively. Of the 46 patients who underwent PCRT, 21 (45.7%) achieved pathologic complete response, including 15 of the 24 (62.5%) who underwent LE. Rectal sparing rate was significantly higher in the PCRT group (11.1% vs. 52.2%, P<0.001). There were no significant differences in 3- and 5-year overall survival and recurrence-free survival regardless of PCRT or surgical procedures. Conclusion PCRT in clinical T2N0 distal rectal cancer patients increased the rectal sparing rate via LE and showed acceptable oncologic outcomes. PCRT may be a feasible therapeutic option to avoid abdominoperineal resection in clinical T2N0 distal rectal cancer.