Utility of an upper echoendoscope for endoscopic ultrasonography of malignant and benign conditions of the sigmoid/left colon and the rectum

OBJECTIVE: The majority of data on colonic endoscopic ultrasound (EUS) are limited to malignant lesions in the rectum and diseases of the anal sphincter. The forward-oblique - Viewing upper echoendoscope has been mostly applied for staging rectal cancer. A front-viewing echocolonoscope is available but has not been widely used because of limited indications and the expense of buying another instrument. The purpose of our study was to evaluate the utility of a forward-oblique - Viewing upper echoendoscope for EUS of malignant and benign lesions of the sigmoid/left colon and the rectum. METHODS: Thirty-two EUS exams were performed for a variety of indications in the rectum and the sigmoid/left colon. The patients were prepared for the exam in a manner similar to the performance of flexible sigmoidoscopy. Flexible sigmoidoscopy was performed in all cases before performing EUS. Surgical path data were reviewed in all cases if the patient had surgery after EUS. RESULTS: Twenty-six exams were done for staging of rectosigmoid carcinoma, follow-up after chemotherapy and/or radiation, or to look for recurrence after resection of colorectal cancer. Surgical pathology results were available in 20 patients. The accuracies of EUS were 85% for T staging and 80% for N staging. Six EUS exams were for benign causes, including evaluation for the presence of a perirectal abscess in two (no abscess found), to rule out rectal varices in one (EUS confirmed rectal varices), and evaluation of submucosal lesions. One patient subsequent to EUS imaging also underwent a linear EUS-guided fine-needle aspiration of a submucosal mass in the rectum with the fine-needle aspirate consistent with a myogenic tumor. CONCLUSIONS: The forward-oblique - viewing upper echoendoscope is a versatile instrument that can be applied for EUS imaging of malignant and benign indications not only in the rectum but also in the sigmoid/left colon.