Abstract
Background:
Segmental aplasia of the caudal vena cava with azygos continuation is a congenital malformation macroscopically described in mammals including humans, dogs and rodents. It is usually detected as an incidental finding and the final diagnosis is reached by computed tomography, fluoroscopy or post-mortem dissection.
Case Description:
A 3-year-old guinea pig (Cavia porcellus) presented with subacute dyspnea. A computed tomographic exam was performed for the evaluation of subtle pulmonary changes previously suspected on conventional radiography, and a segmental aplasia of the caudal vena cava with azygos continuation was identified as an incidental finding.
Conclusion:
According to database negative results, this is the first report describing a segmental aplasia of the caudal vena cava and azygos continuation in a guinea pig by computed tomography.

Key words: Small mammal, Interruption caudal vena cava, Vascular malformation, Congenital malformation