Ileal metastasis of colorectal cancer diagnosed by double-balloon endoscopy and resected via laparoscopy: A case report.

INTRODUCTION

Small bowel metastasis of colorectal cancer (CRC) is rare, with a 3.8 % occurrence. Preoperative diagnosis was considered challenging; however, with the development of various endoscopes, diagnosis may now be possible. Most small bowel metastases of CRC are systemic metastatic events, such as direct invasion or disseminated metastasis. Therefore, R0 surgery is difficult to achieve, and local treatment is infrequent.

PRESENTATION OF CASE: A 70-year-old woman underwent laparoscopic left hemicolectomy for transverse colon cancer in 2022 and her final staging was pT4a, N1b, M0, pStage IIIb. One year after surgery, her carcinoembryonic antigen (CEA) level was elevated, and computed tomography (CT) showed no evidence of neoplastic lesions; however, positron emission tomography (PET) showed a 1 cm nodule with a high SUVmax:9.1 concentration near the uterus, suggesting the possibility of a small bowel tumor. Double-balloon endoscopy (DBE) revealed a submucosal tumor in the ileum. A biopsy could not be performed; however, the lesion was marked with ink dots and clips near the lesion. The lesion was diagnosed as solitary, and the patient underwent laparoscopic partial ileal resection. The tumor was located approximately 60 cm from the end of the ileum on the mesenteric side of the mouth, and it was impossible to determine whether it was an extramural or intraluminal lesion. The patient had a good postoperative course, and histopathologic examination revealed small bowel metastasis of transverse colon cancer, with tumor cells infiltrating from the subserosal layer to the intrinsic muscularis propria. The patient has been under observation for 1 year and 4 months after surgery without recurrence.

DISCUSSION: Small bowel metastases of CRC are very rare and have a poor prognosis; DBE can be used to identify neoplastic lesions in the ileum that could not be determined as extraintestinal or small bowel lesions by CT or PET alone. By marking the lesion with dots of ink and a clip, the lesion was determined to be solitary and amenable to R0 surgery. Laparoscopic surgery was chosen because of the ease of confirming the markings near the lesion and because it was minimally invasive. Furthermore, laparoscopic surgery allowed observation of the subdiaphragm, pelvic floor, and entire abdominal cavity. This report is the only case in which ink dots and clips were employed during DBE and subsequently utilized when laparoscopic surgery was performed.

CONCLUSION

We report a case involving a single site of small bowel metastasis after CRC surgery in which the patient underwent laparoscopic resection of the small intestine after locating the metastatic site with DBE and was successfully treated without recurrence. We conclude that if R0 surgery is possible for a single site of small bowel metastasis, it may contribute to an improved prognosis. Endoscopy is useful for detecting small intestinal tumors, and a single site of small bowel metastasis is a good indication for laparoscopic resection.