Amyloidosis in pigtailed macaques (Macaca nemestrina): pathologic aspects.

The pathologic aspects of 248 cases of amyloidosis in pigtailed macaques (Macaca nemestrina) at the Washington Regional Primate Research Center from 1971 through 1985 were studied. Amyloid was present in the spleen, liver and gastrointestinal (GI) tract, either alone or in combination, in nearly 75% of the monkeys. Its occurrence declined with age in the spleen and the GI tract, but increased with age in the liver. Both intestinal inflammation and retroperitoneal fibromatosis were strongly associated with amyloid deposition in the GI tract. Monkeys with histopathologic findings of enteritis or enterocolitis and glomerulonephritis were at increased risk of developing amyloidosis. Forty cases of amyloidosis with a history of chronic diarrhea had type AA amyloid by histochemical tests.