Characteristic echographic features of circumscribed cancer

Of 964 amputated breast cancers which had been examined preoperatively by ultrasound and mammography, 147 breast (17.0%) contained macroscopically circumscribed tumors and 596 cases (69.0%) showed infiltrative tumors on examination of the cut surface. It is well known that infiltrative types of cancer show ultrasonic images that usually possess clear cut signs of malignancy, such as jagged augmented boundary echoes and acoustic shadows. On the other hand, circumscribed types of cancer do not usually show such signs, but exhibit lobulated shapes and strong, coarse and non-uniform internal echoes. These latter features are intermediate between those of infiltrative cancers and those of solid benign tumors. As such circumscribed cancers are often difficult to diagnose correctly by ultrasonic techniques. The diagnostic accuracy rates by ultrasound were 88.0% in the infiltrative types and 69.4% in the circumscribed types. The ultrasonic pictures of the 147 cases of such circumscribed tumors are classified and discussed.