坂本 博次

BACKGROUND AND AIMS: Continuous low-pressure saline perfusion in endoscopic submucosal dissection (ESD) combines drainage tubes with saline-immersion therapeutic endoscopy, eliminating bubbles from high-frequency devices, enhancing visualization, and maintaining a deflated lumen. We applied this technique to safely resect a large circumferential lesion in the remnant rectum after the Hartmann's procedure where the mucosa was very fragile. METHOD: An 82-year-old man with a 90-mm circumferential laterally spreading tumor in the Hartmann's remnant rectum underwent ESD. A nasogastric drainage tube was inserted in an alpha shape, and continuous low-pressure saline perfusion in ESD was performed. The "Asclepius tube" technique also was used to maintain stable drainage and lumen deflation. RESULTS: The procedure was completed safely within 140 minutes, with excellent visibility and no adverse events noted. Pathology showed an intramucosal, well-differentiated adenocarcinoma with negative margins. A total of 4000 mL of saline was infused, 85% of which was recovered through the drainage tube. CONCLUSIONS: Continuous low-pressure saline perfusion in ESD is a safe and effective technique for large lesions in the Hartmann's remnant rectum, providing stable lumen collapse, enhanced visibility, and minimal mucosal trauma.

BACKGROUND: Although endoscopic diagnosis of primary small intestinal lymphoma (PSIL) is important, the association between endoscopic findings and histologic types remains unclear. This study aimed to evaluate the diagnostic accuracy of endoscopic classifications and biopsies in PSIL. METHODS: We retrospectively reviewed 100 lesions from 49 patients with PSIL who underwent double-balloon enteroscopy between 2005 and 2020. Endoscopic findings were classified into six macroscopic types: polypoid, ulcerative, multiple nodules, diffuse, concentric stenosis, or unclassified. RESULTS: Of the 100 lesions, 47 were multiple nodules, 32 were ulcerative, 8 were polypoid, 7 were diffuse, 4 were concentric stenosis, and 2 were unclassified. Diffuse large B-cell lymphoma (DLBCL) was mainly ulcerative (72%) or polypoid (75%), whereas follicular lymphoma appeared as multiple nodules (98%) or concentric stenosis (100%) (p<0.001, Cramér's V=0.41). The ulcerative type was associated with DLBCL (sensitivity, 0.74; specificity, 0.87), and multiple-nodule type were associated with follicular lymphoma (sensitivity, 0.75; specificity, 0.97). The overall diagnostic yield of the biopsy was 95%. Interobserver agreement was substantial (κ=0.69; agreement, 78%). CONCLUSIONS: Endoscopic findings were significantly associated with histologic types. Endoscopic findings and biopsies provide a high diagnostic yield, supporting their central role in the diagnostic management of PSIL.

INTRODUCTION: Follicular lymphoma is an indolent B-cell lymphoma that can involve the gastrointestinal tract, most commonly the small intestine. Although rituximab-based therapy is effective, transformation to diffuse large B-cell lymphoma (DLBCL) can occur and becomes difficult to diagnose after CD20 loss. CASE PRESENTATION: We report the case of a 64-year-old woman initially diagnosed with primary small intestinal follicular lymphoma who subsequently developed transformation to DLBCL 2 years after rituximab therapy. Double-balloon enteroscopy revealed progression of mucosal lesions, raising suspicion of histologic transformation. However, endoscopic biopsy was inconclusive because of the loss of CD20 expression, likely resulting from prior rituximab therapy. Surgical resection was performed to relieve intestinal obstruction and to establish a definitive diagnosis. Histopathological examination confirmed transformation to CD20-negative DLBCL. CONCLUSION: This case highlights the diagnostic limitation of endoscopic biopsy following rituximab therapy. Therefore, clinicians should be cautious in relying solely on endoscopic findings and remain open to surgical intervention to achieve a timely and accurate diagnosis.