Clinicopathological Characteristics of Macroscopic Morphological Types of Colorectal Muscularis Propria Carcinoma

Ichizo Watanabe, Masao Toyoda, Hitoshi Hara, Junji Okuda, Toshiyuki Tenjo, Keitaro Tanaka, Tetsuhisa Yamamoto, Hiroshi Kawasaki and Nobuhiko Tanigawa

Department of General and Gastroenterological Surgery, Osaka Medical College

To investigate the clinicopathological characteristics of various macroscopic morphological types of colorectal muscularis propria (mp) carcinoma, we studied 91 colorectal mp carcinomas resected surgically from 1979 to 1997. The 91 mp carcinomas were morphologically classified as: superficial and flat tumors with minimal elevation (type 0, N=4); protuberant type (type 1, N=16); ulcerated type with clear margin (type 2, N=70); and ulcerated type with infiltration (type 3, N=1). The 20 mp tumors of types 0 and 1 were considered as group A and the 71 mp tumors of types 2 and 3, as group B. Tumor histologies in group A were well and moderately differentiated adenocarcinomas. Howere, group B included not only well and moderately differentiated adenocarcinomas but also pooly differentiated and mucinous adenocarcinomas. Lymph node metastasis was present in 17 (18.7%) of the 91 cases of colorectal mp cancer. It was detected in 3 (14.3%) of the 21 cases in group A and in 14 (19.7%) of the 71 cases in group B. The incidence of lymph node metantasis was not signigicantly different between the 2 groups. Lymph node metastasis in group B, however, was found in more distant regions than that in group A. The frequency of lymphatic invasion was 69.2% (63/91) of all mp carcinomas. Those in groups A and B were 65.0% (13/20) and 70.4% (50/71), respectively. Venous invasion was found in 40.7% (37/91) of all cases, 25.0% (5/20) in group A, and 45.1% (32/71) in B. Survival data indicated a more favorable prognosis in group A than B (p=0.08). These findings suggest that the mp carcinoma in group B with less differentiated histology and remote lymph node metastasis, as well as poorer prognosis, should be treated more intensely.

Key words
colorectal muscularis propria carcinoma, macroscopic morphological type

Reprint requests
Ichizo Watanabe Department of General and Gastroenterological Surgery, Osaka Medical College 2-7 Daigakumachi, Takatsuki City, 569-8686 JAPAN

Accepted
June 22, 1999

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