[Clinicopathologic evaluation on colorectal laterally spreading tumor (LST)].
Clinicopathologic characteristics of 92 colorectal laterally spreading tumors (LST) endoscopically or surgically resected were examined. Lesions were macroscopically classified into two categories according to their surface structure :(1) granular type (G type, 47 lesions), (2) flat type (F type, 45 lesions). The size (maximum diameter) of G type lesions was 24.7 +/- 11.3 mm (Mean +/- SD) and that of F type lesions was 14.2 +/- 7.4 mm. The size of G type lesions was significantly larger than that of F type lesions (p < 0.01). Among G type lesions, cancerous lesion was present in 2 (25.0%) of 8 lesions 10-14 mm in diameter, 2 (22.2%) of 9 lesions 15-19 mm in diameter and 19 (63.3%) of 30 lesions more than 20mm in diameter. Regarding F type lesions, cancerous lesion was present in 15 (46.9%) of 32 lesions 10-14 mm in diameter, 4 (80.0%) of 5 lesions 15-19 mm in diameter and 8 (100%) of 8 lesions more than 20mm in diameter. The incidence of carcinoma in F type lesions was higher than that in G type lesions irrespective of size. F type lesions with carcinoma showed a trend toward a higher frequency of submucosal invasion and F type lesions with adenoma revealed tendency of showing severe atypia in comparison with G type lesions. The adenomatous component of LST showed a tubulo-villous architecture in 13 (28.3%) of 46 G type lesions, however none of F type lesions had a tubulo-villous component. These results indicated that clinicopathologic characteristics of F type are obviously different from G type. Furthermore, F type had a higher malignant potential than G type and is thought to have a more important role as a precursor of colorectal carcinoma than G type.
Okamoto
T
T
First Department of Internal Medicine, Hiroshima University School of Medicine.
Tanaka
S
S
Haruma
K
K
Hiraga
Y
Y
Kunihiro
M
M
Goishi
H
H
Tanimoto
T
T
Sumii
M
M
Yoshihara
M
M
Sumii
K
K
Kajiyama
G
G
Shimamoto
F
F
D000230:Adenocarcinoma / Q000473:pathology* / Q000601:surgery; D000368:Aged; D003113:Colonoscopy; D015179:Colorectal Neoplasms / Q000473:pathology* / Q000601:surgery; D004724:Endoscopy; D005260:Female; D006801:Humans; D007413:Intestinal Mucosa / Q000601:surgery; D008297:Male; D008875:Middle Aged; D009361:Neoplasm Invasiveness