How Often Does Alpha-Methylacyl-CoA-Racemase Contribute to Resolving an Atypical Diagnosis on Prostate Needle Biopsy Beyond That Provided by Basal Cell Markers?

Interpretation and use of AMACR staining should be executed with caution. A negative AMACR stain can be seen in approximately 18% of cases considered to be cancer based on H&E stain combined with negative basal cell markers. A positive AMACR staining converted an atypical diagnosis, based on suspicious histology and negative basal cell marker stains, to cancer in approximately 10% (34 of 307) of cases thought to be atypical by contributing pathologists and in approximately 50% (34 of 76) of cases thought be atypical on expert review by a specialist in genitourinary pathology.