A case of AA amyloidosis with biliary cystadenoma and cervical thymoma in a striped skunk (Mephitis mephitis).

A 6-year and 11-months-old male striped skunk, Mephitis mephitis, showed inappetence and died. Necropsy revealed multiple hepatic masses, an enlarged spleen, wedge-shaped lesions in the kidneys, and a cervical cyst with white nodules. Histopathologically, the hepatic masses were diagnosed as biliary cystadenomas accompanied by chronic inflammation, the cervical cyst was a thymoma, and the splenic and renal lesions were diagnosed as infarctions. Amorphous eosinophilic material was observed in the liver, spleen, and kidney. These proteinaceous deposits were positive for Congo red staining with yellowish to green birefringence under polarized light. These deposits were immunohistochemically positive for amyloid A (AA). This report describes the pathological features of AA amyloidosis, biliary cystadenoma and cervical thymoma in a striped skunk.