Case Study

Nodular pancreas and ascites in a 10 year old MN DSH cat

This 10-year-old MN DSH cat with controlled hyperthyroidism presented for partial anorexia, chronic diarrhea, and abdominal distension as noted by the owner. The physical exam confirmed a non-painful abdominal swelling, atrophy of the lumbar musculature, and a poor haircoat. Palpation was normal except for the suspicion of ascites. The CBC at the time of presentation was normal but had demonstrated a mild leukocytosis with a left shift one month previously; this had responded to antibiotics and had since normalized.

This 10-year-old MN DSH cat with controlled hyperthyroidism presented for partial anorexia, chronic diarrhea, and abdominal distension as noted by the owner. The physical exam confirmed a non-painful abdominal swelling, atrophy of the lumbar musculature, and a poor haircoat. Palpation was normal except for the suspicion of ascites. The CBC at the time of presentation was normal but had demonstrated a mild leukocytosis with a left shift one month previously; this had responded to antibiotics and had since normalized. Blood chemistry analysis demonstrated progressively elevated ALP and mildly elevated lipase. All other parameters were normal. The hyperthyroidism was controlled, and the T4 was within normal limits.

DX

Suggestive for carcinomatosis, lymphomatosis, FIP.

Sonographic Differential Diagnosis

Suggestive for carcinomatosis, lymphomatosis, FIP. Deductive reasoning (see comments) has eliminated other causes of ascites such as passive congestion, portal hypertension, and protein losing disease (albumin was normal). No anemia is present therefore this would not be hemoabdomen. Hence, lymphatic obstructive disease is likely causing the ascites formation.

Image Interpretation

The abdomen in this patient presented ascites with a nodular pancreatic region and hypoechoic pancreatic nodules suggestive of carcinoma. Image 1 reveals a distinct hypoechoic nodule in the region of the pancreas with surrounding mildly irregular omentum. Video 1 reveals a multifocal hypoechoic region that deviates form the normal curvilinear contour of the pancreas. Surrounding anechoic ascites is present. Video 2 shows that the liver is uniform with a volume contracted portal vein and normal common bile duct.

Outcome

Given the normal albumin levels, normal intrahepatic and vena cava vasculature, normal echocardiogram, and the presence of non septic fluid, abdominal lymphatic obstructive disease was of concern. The resultant differential diagnosis remained carcinomatosis, lymphomatosis, FIP, and less likely, pancreatitis. The nodular and hypoechoic changes in the pancreas would suggest carcinomatosis presentation but would necessitate surgical biopsies for confirmation. US-guided procedures, in the author’s (EL) opinion, typically provide poor yield in these types of presentations. The patient was euthanized due to progressive disease without a definitive tissue diagnosis.

Comments

The liver is uniform with a volume contracted portal vein and normal common bile duct which would suggest no significant liver pathology. Therefore, portal hypertension is likely not a cause for the ascites. In cases of portal hypertension the portal vein is prominent and there is usually diffuse liver disease and corresponding hepatic changes such as fibrosis, remodeling and cirrhosis. An exception is the rare case of portal vein hypoplasia that can cause portal hypertension. Portal vein velocities of > 15 cm/sec on pulsed wave Doppler could definitively rule out portal hypertension as a cause of the ascites formation. In addition the hepatic veins are essentially nonexistent, therefore passive congestion from thoracic disease (Right CHF or obstructive masses, pericardial effusion) can be ruled out as well.

Clinical Differential Diagnosis

Ascites – neoplasia, pancreatitis, chronic hepatic disease with portal hypertension, passive congestion due to cardiac/caval obstructive disease, obstructive lymphatic disease, FIP, hemoabdomen secondary to neoplasia.