Diagnosis of amyloidosis by abdominal fat aspiration. Analysis of four years' experience

Abdominal fat aspiration samples from 443 consecutive patients were examined for amyloid after Congo red and hematoxylin staining. Of the aspirates from 83 patients known to have systemic amyloid disease prior to the biopsy, 70 (84 percent) were found to yield positive results. The results for four aspirates from patients with localized amyloid disease were negative. Of the aspirates from 356 patients of unknown clinical status referred for analysis by outside physicians, 26 (7 percent) yielded positive results for amyloid. On review of the clinical records of these 26 patients, 11 had proved systemic amyloidosis demonstrated on biopsy of another site; all had a clinical course consistent with amyloid disease. In no case was amyloid found in a fat aspiration sample from a patient without clinical evidence suggestive of systemic amyloid disease. This study supports the proposal that abdominal fat aspiration is the diagnostic procedure of choice in the evaluation of amyloidosis since it requires no specialty consultation or technical expertise, causes minimal patient discomfort, and is accompanied by virtually no risk of morbid complication. A positive result has a high predictive value of amyloid disease in patients of unknown clinical status.