Ancillary alpha-methylacyl-CoA racemase immunocytochemistry in the diagnosis of adenocarcinoma of the prostate in urinary cytology: a case report

BACKGROUND: Alpha-methylacyl-coA racemase (AMACR) was recently shown to be a sensitive immunohistochemical marker for substantiating a diagnosis of adenocarcinoma of the prostate. Its applicability to exfoliative urinary cytology has not been investigated before. CASE: The patient was a 77-year-old male with a history of persistent intermittent hematuria who was evaluated with urine cytology. Cytopathologic studies were interpreted to demonstrate "atypical urothelial cells." The patient was evaluated with computed tomography, which demonstrated new left hydroureter and hydronephrosis. He underwent cystoscopy, which showed an abnormal left hemitrigone with the left ureteral orifice obscured by an infiltrative mass. This area was biopsied, and histologic studies of the tissue chips demonstrated underlying prostatic adenocarcinoma directly invading the urothelium. We used AMACR immunoreactivity on a retrospectively studied, catheterized urine slide to confirm the diagnosis. CONCLUSION: This case suggests that combined cytomorphology and immunocytochemisty for AMACR may allow an accurate identification of cells of prostatic adenocarcinoma when cytomorphologic studies or the clinical history raises the differential diagnosis of prostate cancer presenting with exfoliation of malignant cells into the urine.