This study assessed the value of an atypical small acinar proliferation (ASAP) workup consisting of preparing new recut sections from the paraffin block and performing H&E-stained sections and immunostains (using the antibody cocktail for p63, cytokeratins 5 and 14, and alpha-methylacyl coenzyme A racemase) on the slides. We compared the ASAP workup with the interval workup, the common practice of performing the same immunostains on the saved interval sections, in 105 cases because of focal glandular atypia on the original H&E-stained sections. There were no specimens in which only the interval workup showed a changed diagnosis, but there were 23 specimens (21.9%) in which the preliminary diagnosis was changed to a definitive diagnosis of carcinoma (10 specimens) or a specific benign diagnosis (13 specimens) based solely on the findings of the ASAP workup. The ASAP workup is recommended as a very useful histologic tool for resolving diagnostic problems in prostate needle biopsy specimens.