| [ Summary ] |
We studied the clinical significance and problems of dealing with "laterally spreading tumors (LST)" of the colon and rectum, examining 275 such lesion, which were larger than 10mm in diameter. We used the term "LST" instead of referring to superficial spreading tumors of the esophagus and stomach, not as one of the macroscopic types of colorectal tumor. LST findings could be divided into two categories, as follows ; 105 lesions of the flat-type LST (F-LST) and 170 lesions of the granulonodular-type LST (G-LST). The average maximum diameter of G-LST is significantly larger than those of F-LST. F-LST larger than 20mm in diameter revealed a significantly higher incidence of focal carcinoma than those less than 20mm in diameter, however, G-LST revealed a lower incidence of focal carcinoma in spite of their large size. Furthermore, F-LST showed a significantly higher invasive potential than G-LST. According to both of these features of LST and the technical limits of one-chance strip biopsies in size (20mm in diameter), we would propose that the definition for LST might include those of a size larger than 20mm in diameter. |