CT – Heart base tumor and intravascular expansion with CHF and compressive myelopathy in a 8 year old M mixed breed dog

History

This 8 year old M mixed breed dog presented with pleural effusion, facial swelling . Fluid analysis showed modified transudate. On echo a 4.5 cm suspected soft tissue mass is identified at the heart base.

DX

• Heart base tumor with intracardial (right atrum and auricular appendage) and intravascular expansion (cranial vena cava and azygos vein). • Right-sided congestive heart failure caused by the tumoral obstruction with differential distribution between the trunk, front- and hind-end. • Paraneoplastic and/or congestive pleural, pericardial and peritoneal effusion • Deep cervical compressive myelopathy secondary to dilation oft he vertebral venous sinus.

Image Interpretation

CT of the thorax – A large non-uniformly enhancing mass of approximately 4.5 cm diameter is obstructing the right atrium and auricular appendage. A large tumor thrombus extends 4 cm into the cranial vena cava and 2 cm into the azygos vein. The cranial vena cava is expanded at 1.5 cm level with the tumor thrombus and dilated at 2 cm cranial to it. The brachycephalic and jugular veins are dilated as well as the ventral vertebral venous sinus. The marked vertebral venous sinus dilation causes a bilateral mass effect on the floor of the vertebral canal within the ventral epidural space and significant spinal cord compression.

The caudal vena cava presents mild dilation at 1.8 times the aortic diameter. The right venricle is compressed. There is moderate bilaterally symmetric pleural effusion and mild hydrostatic atelectasis of the lung. Scant pericardial and peritoneal effusion is noted as well as a gallbladder wall edema and mild generalized hepatomegaly with dilation of the hepatic veins. The lung parenchyma and mediastinal lymph nodes are negative for metastatic spread. The sternal lymph node presents mild reactive hyperplasia. The spleen is volume contracted and negative for metastatic spread.

Outcome

Differentials include chemodectoma/paraganglioma, ectopic thyroid carcinoma, hemangiosarcoma, lymphosarcoma, other.

Empirical chemotherapy may be considered as options for tumor sampling appear to be limited owing to the intracardial and intravascular expansion.
The expected success of palliative surgical measures such as pericardectomy and cytoreduction appears to be limited as well.

Consider oncology and cardiovascular surgeon consult for discussion of further options.