UK DIAGNOSTIC ROUNDS
Metastatic Carcinoma in a Ewe Drs. Michelle Arnold and Uneeda Bryant
University of Kentucky Veterinary Diagnostic Laboratory A special thanks to Dr. Ben Stivers, referring veterinarian.
michelle.arnold@
uky.edu
• (859) 257-7190
A 3-year-old, 180-pound, female Katahdin presented with a three-day history of depression, inappetence, polydipsia, and diarrhea that contained flecks of blood. Te ewe had been wormed three weeks prior by the
owner. Te veterinarian administered fluids and began amprolium (CORID®) therapy for possible coccidio- sis. Blood samples were collected in EDTA (lavender-top) and heparin (green-top) tubes for complete blood count (CBC) with differential and a chemistry panel. Additionally, two fecal swabs, one for Salmonella PCR and one for aerobic culture were submitted. Te CBC indicated a slightly elevated leukocyte count consis- tent with a stress leukogram with a 3:1 ratio of neutrophils to lymphocytes and lack of a left shift. Chem- istry analysis could not be performed; although heparinized plasma can be used for most clinical pathology tests, the UKVDL’s automated chemistry instrument is only validated for serum. Te owner declined to draw an additional blood sample for a chemistry panel. Te Salmonella PCR was negative, and the aerobic culture yielded nonpathogenic bacteria. Two weeks later, the owner reported that the ewe continued to be inappetent and polydipsic, but the diarrhea had resolved and she was staying with the flock. Te referring veterinarian made a second visit and submitted EDTA and serum (red-top) tubes for CBC and chemistry. Te CBC again indicated a stress leukogram with a massive ratio reversal of 6.5: 1 neutrophils to lympho- cytes. Te chemistry panel revealed multiple, clinically relevant, abnormal values including a markedly elevated gamma-glutamyl transferase (GGT=596 U/L; reference range: 20-40 U/L), an elevated blood urea nitrogen (BUN=57 mg/dL; reference range: 10-20 mg/dL), elevated total bilirubin (1.4 mg/dL; reference range: 0.1-0.6 mg/dL), elevated alkaline phosphatase (ALP=316 U/L; reference range: 40-150 U/L), elevat- ed aspartate aminotransferase (AST=361 U/L; reference range: 90-160 U/L); and elevated serum calcium (17.2 mg/dL; reference range: 11.5-12.8 mg/dL). In addition, sodium, glucose and albumin were slightly low and chloride was slightly high. Te marked elevation in GGT can occur with cholestasis and is con- sidered an important indicator of hepatobiliary disease in ruminants. Differentials for biliary obstruction or constriction included cirrhosis, hepatic abscessation, fascioliasis, cholelithiasis, hepatic lipidosis, chronic hepatocellular damage, and neoplasia.
Tree days after the second blood draw, the ewe presented in lateral recumbency and was unable to stand. Due to her poor prognosis, she was humanely euthanized and submitted for necropsy.
Te 128-lb ewe was submitted in good postmortem preservation and good body condition. Internal fat stores (subcutaneous, intrathoracic and intra-abdominal) were abundant. Multifocal and coalescing, vari- ably-sized, mottled white to tan to red, firm, roughened, spherical to irregularly-shaped nodules were widely distributed throughout all liver and lung lobes (Figure 1). Te nodules ranged from 0.3 cm to 6 cm in diameter and frequently contained centrally located depressions. Cut sections of liver and lung demonstrat- ed infiltration into the underlying parenchyma. Te heart had multiple pale and dark red foci within the myocardium and endocardium. Small (0.2 cm - 0.3 cm) white to tan foci were also present on the valvular leaflets of the tricuspid and mitral valves. Similar tan to red nodules of various sizes were observed within the omentum, abdominal lymph node, pericardium, diaphragm, kidneys, and subjacent to the pancreas. Two small fetuses occupied the lumen of the uterus. No other significant gross lesions were observed.
Histologically, the liver, lung, kidney, peripancreatic and omental connective tissues, diaphragm, pericardi- um, abdominal fat and lymph node were expanded by variably-sized, clusters, cords, lobules, islands, nests and acinar-like structures of neoplastic cells that exhibited or lacked varying degrees of hyalinization and keratinization. Marked amounts of desmoplastic tissue surrounded the neoplastic cells and effaced extensive regions of normal parenchyma. Two to five mitotic figures were observed per high-powered-field. Multiple regions of necrosis were located throughout the masses. Neoplastic cells were located in multiple vascular
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