Student Case Presentation
Mesothelioma in a Mature Beef Cow
| Date/Time: |
9/12/2024 4:00 pm
|
| Presenter: |
Chris Box |
| Veterinary School: |
TAM |
Abstract:
An 11-year-old angus cow presented for anorexia, lethargy, and worsening abdominal distension of one week’s duration. According to the owner, she was approximately seven months into gestation. Physical abnormalities included tachycardia, tachypnea, and increased bronchovesicular sounds bilaterally. Her abdominal contour was distended ventrally and bilaterally (pear-shaped). Despite abdominal distension, her body condition score was 3/9. A prominent fluid wave was discovered upon abdominal ballottement. Rectal examination discovered diffuse crepitus palpable over all tissues and enlarged sub-lumbar and sub-iliac lymph nodes. The uterus was non-gravid. Initial differential diagnoses following physical examination included bovine lymphosarcoma, diffuse peritonitis, uroabdomen, gastrointestinal obstruction, severe pneumonia, and mesothelioma. Ancillary diagnostics selected included a complete blood count (CBC), serum chemistry, and abdominal ultrasound. Results of the CBC and serum chemistry were unremarkable. Abdominal ultrasound revealed large amounts of diffuse hypoechogenic free fluid throughout the abdomen. Further diagnostics including abdominocentesis and bovine leukemia virus testing were considered at this time. However, due to the grave prognosis of potential neoplasia and rapidly declining condition of the cow, the owners elected euthanasia. Necropsy findings included approximately 75 liters of free fluid in the thoracic cavity, and 300 liters of free fluid in the abdominal cavity. All peritoneal and parietal surfaces were covered with multifocal to coalescing, raised, yellow, firm nodules. Multiple fibrous adhesions were found as well between the pulmonary pleura and the parietal pleura. Histopathology of selected tissues conclusively diagnosed mesothelioma. Mesothelioma is a relatively uncommon condition of cattle. Presenting clinical signs in this case led us to multiple more common differential diagnoses. Most of these were eliminated from consideration by rectal palpation, CBC, and serum chemistry findings. An antemortem diagnosis of this condition could have been made from cytology of abdominocentesis fluid; however, from an economic and animal welfare standpoint, the decision of euthanasia was most appropriate.
