The Clinical Implication of Incidental Prostatic Amyloidosis

Objective: To describe the clinicopathologic features of patients with incidental prostatic amyloidosis. Patients and methods: We queried the genitourinary pathology database at Mayo Clinic Arizona for prostate specimens which showed amyloid deposits. Congo red stain was used for the diagnosis of amyloidosis and amyloid subtype was performed analysis using Liquid chromatography tandem mass spectrometry. We reviewed the patient's medical charts for past or subsequent diagnosis of systemic amyloidosis and clinical course. Results: Prostatic amyloidosis was identified in 7 patients between 2008-2018. Median age was 79 years (range 69-84) and median follow-up was 5 years (range 0-11). Benign prostate tissue was found in 4 patients, and prostate cancer was diagnosed in 3 patients. Amyloid subtyping was available in 6 patients and was consistent with Amyloid transthyretin Amyloidosis. Liquid chromatography tandem mass spectrometry did not detect an amino acid sequence abnormality in the transthyretin protein in any of the patients. Five of 6 patients were diagnosed with cardiac amyloidosis, which preceded and followed the diagnosis of prostatic amyloidosis in 1 and 4 patients, respectively. Of these 4 patients, 2 were diagnosed immediately and as a consequence of the diagnosis of prostatic amyloidosis, and the remaining 2 3 and 4 years later. Conclusion: Incidental prostatic amyloidosis should prompt systemic and cardiac evaluation for amyloidosis. In patients with suspected cardiac amyloidosis, prior prostate specimens should be reviewed for the presence of amyloidosis.