Diagnosis and treatment of laterally spreading tumor (LST) through endoscopy / 解放军医学杂志

ABSTRACT

Objective The laterally spreading tumor (LST) of the large intestine have received a great deal of study in Japan, but no report of such cases was found in China. We here of report 46 cases of LST (47 lesions, because one of the patients was found to have two lesions) diagnosed in our hospital in last two years. The morphological features under endoscopy, pit pattern, pathology and treatment under endoscopy were studied. Methods The 47 lesions of LST were found in a total of 5 735 patients who underwent colonoscopic examination in the last two years (from 01-12-2000 to 30-11-2002). The site, size and morphological features of LST were recorded, and the pit pattern was classified with magnification. 42 patients (totally 42 lesions) received colonoscopic surgery, and the rest refused to accept endoscopic therapy, therefore only a biopsy was done for pathological study. In those patients who accepted colonoscopic surgery, 14 patients were treated by mucosal resection (EMR) after injection of saline solution, 24 were treated by piecemeal mucosal resection (EPMR) after injection of saline solution, in 3 patients the lesion was removed by high frequency loop resection, and Cap-EMR was performed using distal hyaline hat attachment fitted to the end of endoscope. The resected or biopsy specimens were studied pathologically. Results 47 lesions of LST were found in a total of 5863 patients who underwent colonoscopic examination. The distrihution of LST lesions were as follows. 22 lesions were situated in the rectum, 10 lesions in the sigmoid colon, 7 lesions in the descending colon, 4 lesions in the transverse colon, 2 lesions in the ascending colon, and 2 lesions were located in the cecum. Macroscopic type 25 lesions were homogeneous granular type, 12 lesions were mixed nodular granular type, 8 lesions were flat elevated type, and 2 lesions were pseudo-depressed type. The pit pattern as revealed under magnifying endoscopy indicated that 2 lesions were of type II pit, 8 lesion of type II+III L pit, 9 lesions of type III L pit, and 28 lesions of type IV. The pathological diagnosis revealed that 28 lesions were villous adenomas in which 7 lesions showed early malignant degeneration (6 intramucosal cancer and 1 submucosal cancer). 11 lesions were tubular adenomas, in which 1 was intramucosal cancer, 2 lesions were hyperplastic polyp, and 6 lesions were mixed hyperplastic polyps (serrated adenomas). Conclusion The LST manifest some special features, and their incidence may be higher in China than in Japan. EMR or EPMR may be considered as a good method for treatment for LST.