Right atrial myxosarcoma in a dog

A case of right atrial myxosarcoma is described in a Staffordshire bull terrier with a history of weight loss, exercise intolerance and collapse. The diagnosis of an intracavitary cardiac tumour was made on echocardiography. The dog was euthanased. Secondary spread to the lungs and lymph nodes was present. Myxoma is one of the rare intracavitary cardiac tumours and this case is believed to be the 1st report of its more malignant form in the dog.