[Incidence and significance of "atypical acinar proliferation" in transrectal prostatic biopsies]

To determine the incidence of atypical acini in our series, the percentage of prostate cancer and other suspicious or preneoplastic lesions in the successive biopsies and to establish a follow up strategy in these patients.

A total of 117 patients diagnosed with isolated atypical acini or associated with high grade PIN were obtained from our database, 75 (64%) of these were submitted to at least a second biopsy of the gland. The age, PSA, digital rectal examination (DRE), prostate volume, ultrasound nodule and previous pathological diagnosis were compared with the pathology results of the successive biopsies of the gland.

Incidence of atypical acini was 4%. A total of 46.7% of patients undergoing a repeat biopsy presented prostate cancer. We did not find significant differences in the clinical variables studied between patients with or without a definite cancer diagnosis. Patients initially diagnosed with acinar atypia with associated high grade PIN presented a higher incidence of cancer in the repeat biopsy than patients with isolated acinar atypia (p=0.007). A total of 94.3% of all neoplasms diagnosed were detected in the 2nd and 3rd biopsy.

Patients with atypical acini are at high risk of having prostate cancer not detected in the first biopsy. They should, therefore, undergo a second biopsy as soon as possible. There is only a very small probability of detecting cancer after the 3rd biopsy.