The echographic characteristics of fatty tissues and tumors.

Fatty tissues and tumors have been described as characteristically cyst-like on ultrasound examination, with relatively few internal echoes. The authors offer several examples of lipomatous masses and tissues which are markedly echogenic. In vitro studies suggest that this is an inherent property of body fat and is not due to coexistent fibrous tissue or tumor vascularity. The echogenicity of fat has important implications for diagnostic ultrasound: (a) the presence of fat in tissues and masses may be demonstrated by ultrasound, and (b) because the high-level internal echoes blend with the echo pattern of bowel gas and retroperitoneal fat, lipomatous abdominal masses may easily be overlooked.