Abstract

Background/Aims
Laterally spreading tumors (LSTs) of the colorectum are defined as lesions greater than 10 mm in diameter with a low vertical axis that extend laterally along the luminal wall. We analyzed the clinicopathologic characteristics and endoscopic treatment of LSTs on the colorectum. Methods: The 127 colorectal LSTs were collected from January 2005 through February 2007. Those lesions were analysed according to their endoscopic and pathologic findings. Results: 67 LSTs (52.8%) were more than 20 mm in size. Most common involved sites of LSTs were rectum (32.4%) and ascending colon (25.9%). Most common subtype of LSTs were granular-homogeneous type (G-H) (37%). Histologic types were 76 tubular adenomas (59.8%), 24 tubulovillous adenomas (18.8%), 6 villous adenomas (4.8%) and 21 adenocarcinoma (16.6%). Both nodular mixed type (G-NM) and pseudo-depressed type (NG-PD) contained a carcinomatous component with high frequency as compared with the G-H type. Carcinoma invaded into the submucosa were present in 3 lesions of G-NM type and 6 lesions of NG-PD type. Conclusions: LSTs showed different clinicopathologic characteristics depending on the morphologic classification. G-NM type or NG-PD type had more malignant potential than other types. Endoscopists should select an adequate therapeutic strategy for large LST with careful consideration. (Intest Res 2007;5:33-37)

• Keywords: Laterally spreading tumor (LST); Endoscopic mucosal resection; Endoscopic piecemeal mucoal resection