Case 180427 -3

Fourteen-year-old, female spayed, Scottish terrier

The dog was presented for being acutely ill, with possible weight loss over the last three to four weeks. Has been vomiting and lethargic since the day before presentation. On presentation, he had an elevated ALT, ALP, GGT, and bilirubin. A mucocele was noted on ultrasound examination. Surgery was performed to remove the mucocele, and a biopsy of liver was taken during surgery as well and submitted for histologic examination.

This sample was diagnosed similarly as a high grade carcinoma with vascular invasion. Due to a declining quality of life, the owners elected euthanasia with necropsy.

N/A

One wedge section of severely congested liver is examined, in which the hepatic capsule is undulating, and there are increased numbers of biliary profiles, which are frequently dilated,contain mucinous debris and are surrounded by a fine layer of fibrosis. Moderate numbers of neutrophils with fewer lymphocytes and plasma cells surround bile ducts and occasionally infiltrate the biliary epithelium. Aggregates of these inflammatory cells also infiltrate into the surrounding hepatic parenchyma. Moderate numbers of pigment-laden macrophages are scattered throughout the parenchyma and aggregate in the portal regions. Multifocally, there is hepatocellular atrophy in the subcapsular region, and hepatocytes are replaced by fibrous connective tissue. A focal well-demarcated nodule composed of hepatic parenchyma is expanding the surrounding liver parenchyma (nodular hyperplasia). Multifocally bile ducts are surrounded by mucinous material and moderate numbers of neutrophils.

- Reticulin stain: Multifocal lobular collapse is highlighted

- Masson’s trichrome stain: Fibrosis is highlighted blue, with few areas of fibrosis dissecting through the sinusoids

- Rhodanine stain: No copper noted.

- Carbol fuschin stain: Small numbers of hepatocytes have lipofuscin in their cytoplasm.

- Prussian Blue stain: Large numbers of hemosiderin-laden macrophages are highlighted (blue).

- Liver: Moderate, chronic, neutrophilic, lymphoplasmacytic cholangiohepatitis with biliary hyperplasia

- Liver: Mild, chronic, multifocal lobular collapse and intrasinusoidal fibrosis

- Liver: Mild, chronic, multifocal subcapsular hepatocellular atrophy and fibrosis

- Liver: Severe, chronic, hemosiderosis and mild, multifocal lipofucinosis

In this case, biliary obstruction secondary to a gallbladder mucocele is likely the cause of cholangiohepatitis. The mucocele was likely chronic based on the composition of the inflammatory population noted in the liver, as well as the fibrosis. Cholangiohepatitis almost inevitably follows biliary obstruction due to a combination of bile leakage into the surrounding hepatic parenchyma, as well as secondary ascending bacterial infections. In this case, no bacteria were cultured from the bile; however, it is common for bacteria to not be cultured in these cases.

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