Echogenicity of prostate cancer correlated with histologic grade and stromal fibrosis: endorectal US studies.

In this study an attempt was made to clarify some of the causes of the apparent differences in appearance on ultrasound (US) images of prostate cancer. These differences were correlated with histologic grade and the degree of stromal fibrosis present. Fifty-one cancers (diagnosed and evaluated by means of US-guided biopsy or evaluated by means of radical prostatectomy) were studied. There were 30 hypoechoic, ten echogenically mixed, six isoechoic, and five subtly hyperechoic cancers. The degree of stromal fibrosis was minimal in well-differentiated cancers and increased in poorly differentiated cancers. In addition, the more hypoechoic lesions were, in general, the better-differentiated cancers and had less fibrosis. There was a tendency for the isoechoic cancers and those with subtly hyperechoic areas to more often have poor cellular differentiation and a greater degree of stromal fibrosis, but considerable overlap among histologic types was seen.