S100-stained perineural invasion is associated with worse prognosis in stage I/II colorectal cancer: Its possible association with immunosuppression in the tumor.

Perineural invasion (PNI) is known as a poor prognostic factor in colorectal cancer (CRC). Although histopathological evaluation of PNI is usually conducted on hematoxylin and eosin (HE)-stained sections (HE-PNI), it remains controversial whether PNI can be precisely evaluated only by HE-staining, and its concise mechanisms causing worse prognosis remains elusive. In this study, we examined the impact of PNI evaluated by S-100-immunostaining (S100-PNI) on postoperative mortality in 279 consecutive CRC patients and further investigated its association with the tumor immune microenvironment. S100-PNI was present in 67.3% of tumors whereas HE-PNI was present in 18.5%. A 5-year cumulative incidence of death in the S100-PNI-positive group was significantly higher than that in the S100-PNI-negative group. Further statistical analyses revealed that S100-PNI was an independent prognostic factor of all-cause mortality in stage I/II but not in stage III/IV. Importantly, S100-PNI was associated with the altered tumor immune microenvironment. Infiltrating immune cell profiling revealed that stromal lymphocytic reaction, which was inversely correlated with postoperative mortality, was significantly reduced in S100-PNI-positive tumors compared to S100-PNI-negative tumors in stage I/II. These results indicated that S100-PNI was a poor prognostic factor in stage I/II CRC with possible association with immunosuppression in the tumor.

Recurrent severe anemia associated with a jejunal arteriovenous malformation in pregnancy: A case report.

Background: Small intestinal arteriovenous (AV) malformations may cause gastrointestinal hemorrhage, occasionally leading to anemia; however, they are rarely seen in pregnancy. This report presents a case of a pregnant woman who had recurrent severe anemia that was attributed to a small hemorrhagic intestinal arteriovenous malformation. Case Presentation: A 24-year-old pregnant woman (gravida 2, para 1) presented with a low hemoglobin concentration (3.6 g/dL) in her first pregnancy and underwent an emergency cesarean section at 36 weeks due to non-reassuring fetal status. In her second pregnancy, she was hospitalized at 30 weeks with epigastric pain and nausea. A low hemoglobin level (6.6 g/dL) and scant fecal occult blood were revealed upon examination. She was referred to the hospital for further evaluation and pregnancy management. Recurrent blood transfusions were required; however, neither hematemesis nor obvious fecal hemorrhage was observed. At 31 weeks, a cesarean section was performed owing to persistent anemia. Postoperative small intestinal capsule endoscopy and flexible fiberoptic proximal small intestinal endoscopy revealed a suspected bleeding small intestinal arteriovenous malformation. The patient underwent partial resection of the small intestine on hospitalization day 16. Histopathological examination confirmed a small intestinal arteriovenous malformation. The patient had a good postoperative course and was discharged on hospitalization day 24. Conclusions: Small intestinal arteriovenous malformations can bleed during pregnancy. They can go undetected if they spontaneously shrink postpartum. In severe anemia during pregnancy, hemorrhage from small intestinal arteriovenous malformations should be included in the differential diagnosis and promptly investigated even in the absence of gastrointestinal symptoms.