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.