An autopsy study of men with sporadic transthyretin cardiac amyloidosis found that amyloid frequently deposited in the prostate, and the severity of deposition correlated with cardiac amyloid burden. Among 35 cases with prostate samples, amyloid was visible in 18 patients (51%) on hematoxylin–eosin and confirmed in 29 (83%) by Congo red staining and immunohistochemistry.
Deposits in the intraglandular interstitium and extraglandular vessels of the prostate showed the strongest correlation with cardiac amyloid severity. Patients with H&E-detectable deposits had higher cardiac amyloid scores than those without deposits. In this group, cardiac amyloidosis was the cause of death in 6 of 18 patients (33%), compared with 1 of 6 (17%) without deposits and 1 of 11 (9%) who were positive only by Congo red or immunohistochemistry.
Site-specific findings included intraglandular interstitial deposits in 51% of patients by Congo red and immunohistochemistry, intraglandular vascular in 66%, extraglandular interstitial in 14%, and extraglandular vascular in 80%. Detection rates were lower with H&E. Prostatic adenocarcinoma was present in 37% of cases, and two carcinoma foci showed mild amyloid deposition. Peripheral nerve involvement occurred in 17%.
Researchers reviewed autopsies conducted from 2008 to 2023 in Japan. Prostate and heart tissues were sampled, with cardiac sections taken from the atrial and ventricular septa. Staining methods included hematoxylin–eosin (H&E), phenol Congo red, and transthyretin immunohistochemistry. Deposits were graded on a five-point semiquantitative scale and quantified using digital image analysis.
The mean age was 84 years. None of the patients had been diagnosed with cardiac amyloidosis prior to death. Common comorbidities included hypertension (66%), diabetes (26%), and arrhythmia (25%).
Clinical data on musculoskeletal symptoms were incomplete. Transthyretin gene testing was not performed, which means late-onset hereditary amyloidosis could not be excluded. Other amyloid types were not systematically assessed. Sampling was limited to the prostate’s peripheral zone. Thermal changes in transurethral resection specimens could result in nonspecific staining.
“Because hyalinised lesions of blood vessels can be difficult to differentiate from amyloid deposition using H&E staining and may exhibit faint congophilia on pCR-stained specimens, combining special staining methods, such as Masson's trichrome staining, elastica van Gieson staining, or periodic acid-Schiff staining, is useful for a more accurate diagnosis,” said Shojiro Ichimata, MD, of the Department of Legal Medicine, Faculty of Medicine, University of Toyama, and colleagues.
Prostatic amyloid deposition was common in men with sporadic transthyretin cardiac amyloidosis and paralleled the extent of cardiac involvement. Researchers noted that prostate tissue may be a practical site for identifying transthyretin amyloidosis when cardiac disease is not suspected. They advised pathologists to carefully evaluate intraglandular interstitial deposits on H&E because biopsy material may not always include extraglandular tissue where amyloid is often detected.
The authors reported no conflicts of interest.
Source: Pathology
