Question

A 11-year old male castrated Golden Retriever presents for collapse with muffled heart sounds on examination. You ultrasound the heart and obtain the following image; the right atrium (RA) and right ventricle (RV) are labeled. A large mass is seen in the right atrioventricular groove with pericardial effusion. What is the likely diagnosis?

Idiopathic pericardial hemorrhage
Hemangiosarcoma
Chemodectoma
Lymphoma
Pulmonary adenocarcinoma

Answer 1

The likely diagnosis for an 11-year old castrated male Golden Retriever with collapse and muffled heart sounds, who has a large mass in the right atrioventricular groove with pericardial effusion, is hemangiosarcoma, a malignant tumor of the blood vessels.

Step-by-step explanation:

The presence of a large mass in the right atrioventricular groove with pericardial effusion in an 11-year old castrated male Golden Retriever that has collapsed hints towards a potential diagnosis of hemangiosarcoma. Hemangiosarcoma is a common malignant tumor of the blood vessels that often affects the heart and can lead to pericardial effusion and cardiac tamponade, causing collapse and muffled heart sounds upon auscultation.

While other options like idiopathic pericardial hemorrhage, chemodectoma, lymphoma, and pulmonary adenocarcinoma can also be associated with pericardial effusion or masses in the heart region, hemangiosarcoma is the most likely diagnosis considering the dog's breed and the presented symptoms.