Small Animal Radiology and Ultrasound: A Diagnostic Atlas and Text

174 Small Animal Radiolo g y and Ultrasono graphy
Fig. 2-154 A 9-year-old spayed female Golden Retriever was evaluated
for ascites. Auscultation revealed muffled heart sounds. An electrocardiogram
revealed dampened complexes with electrical
alternans. A right parasternal long-axis four-chamber view revealed
severe pericardial effusion (pe). A large, complex mass (arrow) with
cystic areas is present on the right atrium (ra). Also identified is the
right ventricular free wall (rvw). Diagnosis: Right atrial hemangiosarcoma.
Fig. 2-155 A 1-year-old male German Shepherd
dog with ascites. Auscultation revealed muffled
heart sounds. A right parasternal short-axis view
through the ventricles revealed severe pericardial
effusion (pe) and a complex mass (m), with cystic
areas caudal to the heart. The mass did not move
with the heart beat. No diaphragmatic discontinuity
could be visualized. Also identified are the liver (L),
left ventricle (lv), and right ventricle (rv). A pericardiectomy
was performed. Diagnosis: Pericardial
cyst.
pericardial sac. It is more difficult to distinguish this condition from other pericardial diseases
when the liver or spleen, or both, are herniated or when there is fluid as well as the liver
or spleen within the pericardial sac. A sternal deformity; absent, split, or malformed
xiphoid; or absence of sternebrae also may be seen with this condition. A dorsal mesothelial
remnant has been described in cats. 104 This is evident as a curvilinear soft-tissue structure
in the caudal ventral mediastinum ventral to the caudal vena cava. Affected animals usually
are asymptomatic. However, liver abnormalities such as cirrhosis or tumor may result from
the presence of the liver within the pericardial sac for a long period. The condition is congenital
and is the result of incomplete separation of the pleural and peritoneal cavities.