矢野 智則

BACKGROUND/AIMS: 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.

We herein report a kidney transplant recipient with recurrent bleeding due to multiple ileal ulcerations associated with mycophenolate mofetil (MMF). Symptoms persisted despite surgical resection and embolization. Double-balloon enteroscopy revealed multiple ulcerations, and a biopsy helped exclude other causes. The discontinuation of MMF led to rapid symptom resolution and healing of the ulceration. Intestinal complications after renal transplantation vary, and MMF-induced enteritis, although rare, should be considered. This case highlights the diagnostic value of enteroscopy in identifying drug-induced small intestinal injuries and underscores the importance of including MMF in the differential diagnosis of post-transplant gastrointestinal bleeding.