Sessile serrated lesions: Clinicopathological characteristics, endoscopic diagnosis, and management.

The 2019 World Health Organization (WHO) Classification of Tumours of the Digestive System (5th edition) introduced the term "sessile serrated lesion" (SSL) to replace the term "sessile serrated adenoma/polyp" (SSA/P). SSLs are early precursor lesions in the serrated neoplasia pathway that result in colorectal carcinomas with BRAF mutations, methylation for DNA repair genes, a CpG island methylator phenotype, and high levels of microsatellite instability. Some of these lesions can rapidly become dysplastic or invasive carcinomas that exhibit high lymphatic invasion and lymph node metastasis potential. The 2019 WHO classification noted that dysplasia arising in an SSL most likely is an advanced polyp, regardless of the morphologic grade of the dysplasia. Detecting SSLs with or without dysplasia is critical; however, detection of SSLs is challenging, and their identification by endoscopists and pathologists is inconsistent. Furthermore, indications for their endoscopic treatment have not been established. Moreover, SSLs are considered to contribute to the development of post-colonoscopy colorectal cancers. Herein, the clinicopathological and endoscopic characteristics of SSLs, including features determined using white light and image-enhanced endoscopy, therapeutic indications, therapeutic methods, and surveillance are reviewed based on the literature. This information may lead to more intensive research to improve detection, diagnosis, and rates of complete resection of these lesions and reduce post-colonoscopy colorectal cancer rates.

Linked color imaging improves visibility of colorectal serrated lesion by high color contrast to surrounding mucosa.

OBJECTIVES: This study aimed to objectively evaluate the efficacy of linked color imaging (LCI) in diagnosing colorectal serrated lesions by utilizing visibility scores and color differences. METHODS: We examined 89 serrated lesions, including 36 hyperplastic polyps (HPs), 47 sessile serrated lesions (SSLs), and six traditional serrated adenomas (TSAs). Visibility changes were scored by six endoscopists as follows: 4, excellent; 3, good; 2, fair; and 1, poor. Furthermore, images obtained by white-light imaging (WLI) or LCI were assessed using the CIELAB color space in the lesion and adjacent mucosa. We calculated the mean color values (L*, a*, and b*) measured at five regions of interest of the sample lesion and surrounding mucosa and derived the color difference (ΔE*). RESULTS: The visibility scores of both HPs and SSLs in LCI were significantly higher than that in WLI (HPs, 3.67/2.89, P < 0.001; SSLs, 3.07/2.36, P < 0.001). Furthermore, SSLs showed a significantly higher L* value and significantly lower a* and b* values in LCI than the adjacent mucosae (L*, 61.76/58.23, P = 0.016; a*, 14.91/17.58, P = 0.019; b*, 20.42/24.21, P = 0.007), while WLI produced no significant difference in any color value. A similar trend was apparent in HPs. In all serrated groups, LCI revealed significantly greater ΔE* values between the lesion and adjacent mucosa than WLI (HPs, 11.54/6.12; SSLs, 13.43/7.67; TSAs, 35.00/22.48). CONCLUSION: Linked color imaging showed higher color contrast between serrated lesions and the surrounding mucosae compared with WLI, indicating improved visibility of colorectal serrated lesion using LCI.

Successful Treatment of Steroid-resistant Eosinophilic Gastrointestinal Disease with Mepolizumab.

We experienced a case of treatment-resistant eosinophilic gastrointestinal disease (EGID). The patient, a 46-year-old man, presented with a fever, persistent abdominal pain, and an elevated peripheral eosinophil count. Eosinophil infiltration of the intestinal mucosa was also observed, and EGID was diagnosed. Corticosteroid therapy was initiated, but no improvement was seen. However, after mepolizumab (anti-interleukin 5 antibody) was administered, the patient's disease was controlled. Currently, the indications for mepolizumab are limited to bronchial asthma and paraneoplastic eosinophilic polyangiitis, but the experience herein reported suggests its usefulness in the treatment of EGID.

Mucin phenotypes and clinicopathological features of colorectal adenocarcinomas: Correlation with colorectal adenocarcinoma with enteroblastic differentiation.

BACKGROUND: The mucin phenotypes of colorectal carcinoma (CRC) is related to the biological behavior and prognosis. But there has been no studies evaluating phenotypic characteristics in a large number of cases. Furthermore, colorectal adenocarcinoma with enteroblastic differentiation (CAED) is a rare subtype of CRC and having poor prognosis. The aims of this study were to clarify the correlation between mucin phenotypes and tumor development, including biological behavior in CRC, as well as to investigate characteristic of mucin phenotypes in CAED. METHODS AND RESULTS: 974 CRC cases and 42 CAED cases of CRCs were classified five types (large-intestinal, small-intestinal, gastric, mixed, and unclassified) of mucin phenotypes by using immunohistochemistry (IHC). IHC was performed on tissue microarrays with antibodies against followings: MUC2, MUC5AC, MUC6, and CD10. In CRCs, large-intestine type has a relatively better prognosis, small-intestinal type frequently shows venous invasions, and liver metastases, gastric type has more high-histological grades and lymphatic invasions, mixed type shows originating from the right side of the colon, larger tumor size and mucinous type, but less venous invasions and liver metastasis, whereas the unclassified type showed poorer prognosis in overall survival with statistical significance. The majority of CAED were found to be small-intestinal type or unclassified type. CONCLUSIONS: The phenotypic classification is useful for predicting the prognosis of CRCs. Small-intestinal type and unclassified type showed dismal prognosis in CRCs. We speculate that CAED having aggressive behavior and poor prognosis might reflect characteristics of small-intestinal and unclassified types.

Differential diagnosis of ulcerative colitis with increased diarrhea; collagenous colitis or irritable bowel syndrome? A case report.

A 50-year-old man with a 20-year history of left-sided ulcerative colitis (UC) presented to our hospital with sudden onset of watery diarrhea. To this point, he had been treated with mesalazine 2.0 g/day for UC and had maintained remission. We considered that the UC had worsened. We immediately performed surveillance colonoscopy, which revealed a normal mucous membrane. The results of blood laboratory examinations were normal. Histopathology of colonic biopsies revealed new-onset collagenous colitis (CC), with a thickened subepithelial collagen band (SECB) and inactive UC. We herein report the importance of random colonic biopsies to diagnose CC even when the endoscopic appearance of the colon is normal in patients with inflammatory bowel disease with worsened diarrhea.

CV2/CRMP5-antibody-related Paraneoplastic Neurologic Syndrome Associated with Gastrointestinal Stromal Tumor.

Paraneoplastic neurological syndrome (PNS) is a heterogeneous group of neurological disorders caused by immune-mediated inflammatory mechanisms. We herein report a 77-year-old man with CV2/CRMP5-antibody-related PNS associated with a gastrointestinal stromal tumor (GIST). He was admitted for forgetfulness and delusional behavior. His neurological symptoms were subacute, and a whole-body examination revealed a gastric GIST. Serology showed CV2/collapsin response mediator protein (CRMP)-5 antibodies. Partial gastrectomy was performed for the GIST, and the neurological symptoms and serum CV2/CRMP5 antibodies disappeared. No relapse has occurred since the surgery. PNS should be considered in patients with subacute neurological disorders.

Comparison of the clinical performance and usefulness of five SARS-CoV-2 antibody tests.

We examined the usefulness of five COVID-19 antibody detection tests using 114 serum samples at various time points from 34 Japanese COVID-19 patients. We examined Elecsys Anti-SARS-CoV-2 from Roche, and four immunochromatography tests from Hangzhou Laihe Biotech, Artron Laboratories, Chil, and Nadal. In the first week after onset, Elecsys had 40% positivity in Group S (severe cases) but was negative in Group M (mild-moderate cases). The immunochromatography kits showed 40-60% and 0-8% positivity in Groups S and M, respectively. In the second week, Elecsys showed 75% and 50% positivity, and the immunochromatography tests showed 5-80% and 50-75% positivity in Groups S and M, respectively. After the third week, Elecsys showed 100% positivity in both groups. The immunochromatography kits showed 100% positivity in Group S. In Group M, positivity decreased to 50% for Chil and 75-89% for Artron and Lyher. Elecsys and immunochromatography kits had 91-100% specificity. Elecsys had comparable chronological change of cut-off index values in the two groups from the second week to the sixth week. The current SARS-CoV-2 antibody detection tests do not provide meaningful interpretation of severity and infection status. Its use might be limited to short-term epidemiological studies.