Nipper's autopsy pictures
Lump from spleen???
Nipper's histopathlogy report
Pathological changes in various tissues
Sections from necropsy samples of various tissues from a Polecat Ferret, age and sex not specified, were examined microscopically.
LIVER: 3 samples received; 3 sections examined. One of these sections is largely unremarkable apart from a very small, single focus of hepatocytic vacuolar change. One section includes a large, cystic structure lined by a single layer of cuboidal epithelium, which I think is probably the distended gall bladder, but it is filled with blood and fibrinous clot material. The parenchyma surrounding this is markedly congested, the hepatocytes swollen and vacuolated and the portal areas inflamed and fibrosed, with moderate dilatation of bile ducts. In the third section, there is marked bile duct proliferation and marked peribillary, lymphoplasmacytic inflammation. The majority of the proliferated bile ducts are mildly distended with more or less amorphous debris, often admixed with a few neutrophils.
KIDNEY: 1 sample received; 1 section examined. A single area of interstitial fibrosis extends from the capsule down into the medulla and is associated with moderate tubular atrophy and dilatation and a minimal infiltrate of mononuclear inflammatory cells. The remainder of the section is histologically unremarkable.
SPLEEN: 1 sample received; 1 section examined. The splenic pulp is expanded by a combination of congestion and extramedullary haemopoiesis.
LUNG: 2 samples received; 2 sections examined. Microscopy reveals fairly marked congestion accompanied by slightly increased cellularity of the alveolar walls and slightly increased numbers of alveolar macrophages. A large plug of mucoid material admixed with a few neutrophils is present in one of the mainstem bronchi.
HEART: 1 sample received; 2 sections examined. Grossly, this appeared abnormally globose in shape and the lumen of the left ventricle was markedly dilated. Microscopy reveals patchy vacuolar degeneration of myocytes in the left ventricular wall, often accompanied by mild to moderate anisokaryosis and associated with mild interstitial fibrosis. There is minimal inflammation.
ADRENAL GLAND: 1 sample received; 1 section examined. The normal architecture of the gland is largely effaced by a cellular proliferation forming a mass that occupies almost the entire cortex in the section examined, expanding the gland markedly, crossing the capsule and growing into the adjoining adipose connective tissue. It consists of a mixture of cell types, including very large, ballooned cells with clear cytoplasm; medium-sized to large cells with fairly abundant, variably vacuolated, eosinophilic cytoplasm; and smaller cells with a small amount of amphophilic cytoplasm. There are also some interconnecting bands of spindloid cells coursing through the mass. There is little nuclear atypia and only occasional mitoses can be found.
PANCREAS: 1 sample received; 1 section examined. In this section there is patchy, mild interstitial inflammation and fibrosis of the exocrine portion of the gland and there is marked vacuolation of the Islet cells.
DIAGNOSIS: Various pathological changes - see "Discussion" below.
DISCUSSION: There is evidence of fairly severe, chronic cholecystitis and cholangitis, which was probably sufficient to have been causing biochemical changes consistent with hepatic dysfunction. The cause is uncertain, but as there is also mild pancreatitis the possibility of infection ascending the biliary system from the intestine should be considered. Vacuolation of islet cells is often seen in animals with diabetes mellitus.
The heart showed gross and histological changes compatible with dilated cardiomyopathy and the congestion and mild interstitial pneumonia in the lungs may have been associated with this, although few pigmented macrophages ("heart-failure cells") were seen in the sections examined. Cardiomyopathy is fairly common in ferrets, but a definitive cause has not been identified, as far as I am aware. It is particularly common in some American lines, suggesting a possible genetic basis. Cardiomyopathy may also occur secondary to some myocardial infections, especially viruses, and some workers have suggested a dietary deficiency may be to blame. Clinical signs may be seen In animals as young as 1 year of age, but are more common between about 5 and 7 years.
Adrenal tumours of the type seen in this animal, comprising a pleomorphic population of cells, effacing the normal structure of the gland, have traditionally been diagnosed as carcinomas, but there is little published material correlating histological criteria used in diagnosis with clinical outcome and I suspect many such tumours are behaviourally benign and may be better classified as adenoma.
The combination of extramedullary haemopoiesis and congestion, as seen in the spleen of this animal, is a common cause of splenomegaly in ferrets but the cause remains uncertain, although there are many hypotheses.
There is also evidence of mild, patchy, chronic interstitial nephritis, which is unlikely to have been of any clinical significance at this level.
My own comments: