A one-year-old, castrated male domestic short hair cat was admitted with a history of
anorexia, regurgitation and pyrexia for two days. Fever and leukocytosis were identified.
There were a large soft tissue density oval mass in the caudal mediastinum on thoracic
radiographs, a fluid-filled oval mass in the caudal mediastinum on ultrasonography, and
left-sided and ventrally displaced and compressed esophagus on esophagram. On esophageal
endoscopy, there were no esophageal abnormalities. CT findings with a fluid filled mass
with rim enhancement indicated a caudal mediastinal paraesophageal abscess. The patient
was treated with oral antibiotics, because the owner declined percutaneous drainage and
surgery. The patient was admitted on emergency with severe respiratory distress; and
ruptured abscess and deteriorated pleuropneumonia were suspected. With intensive
hospitalization care and additional antibiotic therapy, the patient had full recovery.