Clinicopathological Study on Laterally Spreading Tumor (LST)

Lee, Yeum Seok; Kim, Seon Mun; Yang, Hyeon Woong; Seo, Seung Weon; Seong, Jae Kyu; Na, Byoung Kyu; Lee, Byung Seok; Jeong, Hyun Yong

Abstract

BACKGROUND/AIMS: Laterally spreading tumors (LST) were growthed along the colonic wall. These tumors were high malignant potential compared to colon polyp. We analyzed clinicopathological characteristics of these tumors.
METHODS
From June 1996 to June 2001, twenty nine patients were diagnosed by colonoscopy. These lesions were classificated macroscopic (granular type and nongranular type) and microscopic findings.
RESULTS
20 male and 9 female were enrolled (mean age, 68.1). Among the LST, 41.4% were 20~30 mm in diameter, and 7% were larger than 30 mm. According to macroscopic findings granular types were 72.4% (21/29) and nongranular types were 27.6% (8/29). In macroscopic findings, tubular types were 48.4% (14/29), malignant changes were 31.3% (9/29). Tumor size was only significant factor in malignant potential of LST (p=0.004). Endoscopic mucosal resection was performed in 72.4% (21/29), operation in 8 (27.6%). Rate of submucosal invasion in LST was 3.4% (1/29, sm1). Recurrent rate of endoscopic treatment group was 9.5% (2/21).
CONCLUSIONS
Most of LST were good indication for endoscopic treatment, but larger tumor size and irregular surface of tumor were suspected to be submucosal invasion. Therefore these lesions were performed other procedures as endoscopic ultrasound or computerized tomography for invasion depth.