Hepatic AA amyloidosis in a cat: cytologic and histologic identification of AA amyloid in macrophages |
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| Authors: | Sakurako Neo‐suzuki Takayuki Mineshige Junichi Kamiie Hideki Kayanuma Yukako Mochizuki Masaharu Hisasue Ryo Tsuchiya Kinji Shirota |
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| Affiliation: | 1. Laboratory of Small Animal Internal Medicine, School of Veterinary Medicine, Azabu University, Sagamihara, Japan;2. Laboratory of Veterinary Pathology, School of Veterinary Medicine, Azabu University, Sagamihara, Japan;3. Laboratory of Veterinary Radiology, School of Veterinary Medicine, Azabu University, Sagamihara, Japan;4. Ito Doubutsuaigo Animal Hospital, Ito City, Japan |
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| Abstract: | A 3‐year‐old, spayed female, Domestic Shorthair cat presented with anorexia, lethargy, vomiting, probable hemoabdomen, and multiple masses on the right lateral liver lobe. Clinicopathologic and imaging abnormalities included anemia, azotemia, icterus, and hepatomegaly with hypoechoic masses. On cytologic evaluation of a fine‐needle aspiration of a liver mass there was abundant extracellular pink‐ to purple‐colored material between hepatocytes. The amorphous material was stained with direct fast scarlet (DFS), and green birefringent areas were observed under polarized light, confirming the presence of amyloid. A unique finding on the cytologic smear were macrophages containing amorphous and fibrillar amyloid‐like protein. Histopathologic examination using H&E and Congo red staining confirmed amyloid deposits within the space of Disse, along the sinusoids, portal tracts, blood vessel walls, and within the cytoplasm of macrophages. Immunohistochemical staining with anti‐AA amyloid antibodies further confirmed the presence of AA amyloid. To the author's knowledge, this is the first report of the cytologic finding of AA amyloid protein within macrophages and DFS stain detection of amyloid on a cytologic smear. |
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| Keywords: | Direct fast scarlet liver serum amyloid A systemic amyloidosis |
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