Significant deposition of wild type transthyretin-derived amyloid in the gastrointestinal tract of aged individuals

Wild-type ATTR amyloidosis of the prostate: a case review

The amyloidoses are a rare group of disorders caused by the deposition of amyloid fibrils in organ tissues. Transthyretin-mediated amyloidosis is a subcategory of amyloidosis, which can be further subdivided into hereditary transthyretin-mediated or wild-type (‘senile’) amyloidosis. Involvement of the prostate by any type of amyloidosis is rare, with only a handful of cases reported in the literature. We report here a case of a 64-year-old Caucasian man who was incidentally found to have wild-type transthyretin-mediated amyloidosis of the prostate following a radical prostatectomy for treatment of a localised, Gleason 7 (4 + 3) adenocarcinoma of the prostate. TTR subtyping was confirmed by mass spectrometry. His family history was negative for known amyloidosis, and sequencing of the entire TTR gene was negative for any mutations, so he was therefore considered to have wild-type TTR amyloidosis. He was subsequently found to have additional foci of amyloid deposition in the gastrointestinal tract. Wild-type transthyretin-mediated amyloidosis as an incidental finding in a prostate biopsy is an extremely rare finding. Treatment options for transthyretin-mediated amyloidosis are limited, and further research and treatment options are needed in this rare and difficult to manage disease.

Level of evidence: The level of evidence according to the Oxford Centre of Evidence-based Medicine levels of evidence is not applicable to this case report. Given that this is a rare entity, decisions made in managing this case were based on a level of evidence of 5.

[Senile systemic amyloidosis: definition, diagnosis, why thinking about?]

Senile systemic amyloidosis (SSA) is characterized by infiltration of amyloid transthyretin fibrils in the myocardium. SSA occurs mainly (but not always) in elderly men. SSA leads to hypertrophic and/or restrictive cardiomyopathy complicated by conduction disturbances, atrial arrhythmia and systemic embolization (stroke…). That is why SSA needs a special care and to be diagnosed. Cardiac SSA diagnosis needs to exclude two other forms of cardiac amyloidosis: AL amyloidosis (light chain) and hereditary transthyretin amyloidosis (genetic testing). Scintigraphic 99mTc-DPD heart retention is observed in cardiac amyloidosis. DPD heart retention is more frequent in cardiac transthyretin amyloidosis than in cardiac AL amyloidosis. Specific treatments of cardiac TTR amyloidosis are in development.

Diagnostic value of abdominal wall fat pad biopsy in senile systemic amyloidosis

Senile systemic amyloidosis (SSA) is a main cause of intractable heart failure in elderly individuals. To demonstrate transthyretin (TTR)-derived amyloid deposition endomyocardial biopsy has been commonly carried out in the patients with SSA, but this invasive biopsy technique cannot always be performed in aged patients with severe cardiac dysfunction. During the past 3 years, 11 patients with SSA (6 males and 5 females; ages from 70 to 97 years) were examined. All underwent skin biopsy from the abdominal wall and 8 showed TTR-immunoreactive amyloid deposition (sensitivity: 73%): amyloid deposits were seen mainly in the deep layer of subcutaneous fat tissue and showed a patchy distribution. They were weakly Congophilic, but were strongly immunolabeled by an anti-TTR antibody. The severity and pattern of amyloid deposition in this biopsy of SSA patients were considerably different from those obtained from age-matched patients with TTR-related familial amyloid polyneuropathy. Surgical skin biopsy including the deep subcutaneous fat pad can be performed safely at the bedside and is useful for the histopathological diagnosis of SSA.