Small intestinal perforation of endoscopically unrecognized lesions during peroral single-balloon enteroscopy.

month history of abdominal pain. Com− puted tomography (CT) showed an ab− dominal tumor, peritoneal dissemination, and ascites (l" Fig. 1). Total colonoscopy, including observation of the terminal ileum and esophagogastroduodenoscopy, showed no specific findings. However, be− cause of abnormal radiographic findings of the jejunum, a single−balloon enteros− copy was performed via the anterograde approach using an enteroscope (SIF− Q260; Olympus, Tokyo, Japan) with a flex− ible overtube (ST−SB1; Olympus) [1, 2]. The patient was sedated with midazolam (10 mg IV) but complained of abdominal pain during insertion of the endoscope into the jejunum. Perforation was sus− pected under fluoroscopy before the en− doscope had encountered any lesions. The enteroscope was withdrawn and ab− dominal radiograph and CT scan suggest− ed intestinal perforation (l" Fig. 2). The small intestine was partially resected be− cause the site of the perforation had been confirmed during the laparotomy. Multi− ple whitish tumors had metastasized mainly to the serosa of the intestine and peritoneum. Gross pathological examina− tion revealed that metastatic tumors had invaded from the serosa into the mucosa and created multiple ulcers, one of which was perforated (l" Fig. 3). Histology of the site of perforation revealed a diffuse infiltrate of tumor cells involving all layers of the small intestinal wall (l" Fig. 4). Al− though the tumors were diagnosed as me− tastatic carcinoma by further immunohis− tochemical examination, a diagnosis of metastatic carcinoma of unknown origin was made because further clinical investi− gations could not confirm the primary site of the carcinoma. Forceful distention and traction may pre− dispose to perforation of an already weakened small intestinal wall; there− fore, if fragile lesions are encountered, in− sertion of the endoscope beyond the le− sions is not recommended [3, 4]. How− ever, in our case, perforation occurred be− fore the endoscope had encountered the lesions. Although it may be difficult to prevent such problems, care must be tak− en when using an endoscope in the small Small intestinal perforation of endoscopically unrecognized lesions during peroral single−balloon enteroscopy