Clinical relevance of amyloid in prostate samples: a report on 40 patients

To describe the clinical findings in patients with incidental prostatic amyloidosis.

Retrospective search in the database of the Department of Pathology, Hospital de Bellvitge, for prostate specimens with amyloid. Congo red and immunohistochemical staining of the sections. Review of the patients' clinical charts for symptoms attributable to systemic amyloidosis.

Amyloid deposition in the prostate was identified and reported in 40 patients between 2001 and 2022. Median age was 76.5 years (range = 62-90 years). Prostate cancer was diagnosed in 25 patients. Only four patients had a previous diagnosis of amyloidosis. In the remaining 36 the prostate sample (31 needle biopsies, two transurethral resections (TUR), two simple prostatectomies, one radical cystectomy for bladder cancer) provided the initial diagnosis. Amyloid deposits were mainly located in the wall of small vessels and rarely in the prostatic stroma. Immunohistochemistry was available in 32 cases, 26 of which were positive for TTR. All patients showed at least one symptom indicative of systemic amyloidosis, the most frequent being hearing loss (55%), carpal tunnel syndrome (42,5%) or other osteoarticular symptoms (tendinopathies, osteoarthritis), cataracts (37.5%) and cardiac symptoms (32.5%), among others.

The prostate is a target tissue for amyloid deposition. The incidental finding of amyloid in prostate corresponds, in the majority of cases, to previously undiagnosed systemic TTR amyloidosis in patients lacking signs of heart involvement but having mainly osteoarticular symptoms, hearing and visual impairment.