[Systemic amyloidosis in the elderly: diagnostic value of the test of subcutaneous abdominal fat and the labial salivary glands. Prospective study in 100 aged patients].

Primary and secondary amyloidosis are not uncommon in aging but the diagnosis is rarely made on account of the risk of bleeding in the site of biopsies and the difficulty to distinguish senile from systemic amyloidosis on the biopsy samples. We have studied the frequency of amyloid deposition in the abdominal fat aspirate (AFA), the labial salivary gland (LSG), the temporal arteries (four cases), bone marrow (two cases), digestive tract (four cases) in 100 elderly patients (aged 80 or greater). AFA was positive in 15 percent of the patients and LSG in 5%; both samples were positive in 4%. Four cases of systemic amyloidosis were found (two of the AL and two of the AA type). Sensitivity of AFA was 75%, specificity was 87% and the positive predictive value was 20%. The values were respectively 100%, 99%, 100% for LSG. In 11 patients whose AFA biopsies samples were singly positive, amyloid deposits were found in temporal arteries in four of four cases. We conclude that AFA is too sensitive for the diagnosis of systemic amyloidosis in aging. The responsibility of senile amyloid deposition on AFA should require further investigations. LSG biopsies seem to be a more reliable test for the diagnosis of primary and secondary amyloidosis in elderly.