[Ultrasonic evaluation of peri-intestinal lymph nodes in patients with colorectal cancer]

The aim of this study was to compare the number of lymph nodes detected by sonography with the actual number and nature of the lymph nodes found on histopathological examination. Twenty colorectal specimens with carcinoma were studied. Sonography was performed with the bowel submerged in water and pericolonic lymph nodes were marked on a drawing of the specimen. After fixation, pericolonic lymph nodes were identified by palpation and their location and size were noted on a similar drawing. By comparing the sonographic and histological findings it was possible to determine which nodes had been identified by sonography. Histological examination detected 205 lymph nodes in the 20 specimens. Sixty-four of them (31%) were found by in vitro sonography (25% of the benign nodes, 56% of the malignant nodes). Preoperative endosonographic assessment (performed in 10 of the patients) generally showed fewer lymph nodes than what was subsequently found by in vitro sonography. The inability of sonography to detect more than 56% of the metastatic lymph nodes makes preoperative endosonographic assessment less valuable than hitherto believed.