Abstract
Fifty cases of rectal cancer were examined by transrectal ultrasonography in the last 2 years. Ultrasonograms of tumor were compared with classification of the macroscopic shapes and miroscopic depths of invasion. Patterns of ultrasonograms were classified into 4 types. Type 1 showed invasion which was limited to the proper muscle. Types 2 to 4 showed progressively marked status of invasion, and were classified according to the depths of maximum tumor diameter on ultrasonograms. The ultrasonic depth of tumor invasion was analyzed in the laminal structure which was composed of 5 layers on the ultrasonogram. These ultrasonograms were able to reveal schematically the mode of tumor growth.
