Some biopsies do not show cancer but do show PIN, or dysplasia. Prostatic Intraepithelial Neoplasia is believed to be the most likely precursor of prostate cancer. However, the cells have not yet become cancerous. Pin can be classified as high grade medium grade and low grade. Low grade PIN is less worrisome that the other two grades.
PIN consists of proliferation of prostatic epithelial cells within preexisting glands.
Elevation of s erum PSA in men with PIN alone in needle biopsies may be due to coexistent unsampled prostate cancer. PIN is a microscopic finding which is below the detection threshold for this form of imaging. Today, most urologists and radiologists do not believe that PIN is detectable by ultrasound. PIN is the most likely precursor of prostate cancer. The presence of high or medium grade PIN in prostate needle biopsy indicates a high likelihood of development of prostate cancer in the future.