Left ventricular fibrosarcoma in a 4‐year‐old labrador

Abstract A 4‐year‐old, male, neutered labrador presented for investigations into a single episode of collapse and an intracardiac mass. Echocardiography and computed tomography confirmed the presence of a large soft tissue mass within the left ventricular lumen, which nearly obstructed the left ventricular outflow tract. Chemotherapy treatment with epirubicin was initiated; however, the patient suffered from sudden collapse and death the following day. Gross postmortem examination, as well as histopathological and immunohistochemical findings, were compatible with a fibrosarcoma.