[A case of primary cardiac amyloidosis with amyloid A protein].
A case of cardiac amyloidosis in a 46-year-old male is reported. He was admitted for dyspnea. Physical examination revealed third and forth heart sound and hepatomegaly. Radiographic heart-thoracic ratio was 53%. Electrocardiogram showed first degree A-V block, rS pattern in V1-V4 leads, and ambulatory electrocardiogram showed ventricular tachycardia. Echocardiogram revealed hypertrophy and highly refractile echoes of the left ventricular wall. Endomyocardial biopsy was performed and it demonstrated amyloid fibrils, which were characterized immunohistochemically as Amyloid A (AA) protein, which is generally a constituent in secondary amyloidosis. Urine protein electrophoresis showed lambda type Bence-Jones protein, but bone marrow biopsy was normal. There was no evidence of malignancy, chronic inflammatory disease, or collagen disease. This case was diagnosed as primary amyloidosis with AA protein. It is rare that, in spite of its being a case of primary amyloidosis, its constituent protein is AA protein.