D1ck vet school - Thymoma in buns

Everybody meet a very special bunny called Booboo!

Booboo is a 9 year old rabbit that came to see us last month, all the way from Hampshire in the South of England. Booboo's vets had diagnosed a mass in her chest cavity and had taken a fine needle aspirate confirming the diagnosis as thymoma.

Thymomas are slow growing tumours of the thymus, (a little lymphoid organ located in the upper part of the chest cavity.) Unfortunately these tumours can get very large, compressing the lungs, as well as moving the heart into an abnormal position.

Typical clinical signs include difficulty breathing, exercise intolerance and bulging eyes.

When Booboo arrived she was lethargic, had difficulty breathing when stressed and both her eyes were bulging. Her eyes were protruding due to the tumour compressing some of the large veins in her chest, affecting the return of blood from the head. This in turn leads to an increase in blood volume behind the eye, (in the retrobulbar venous plexus), which causes the bulging appearance.

We initially performed a conscious CT scan of Booboo to measure the size of the tumour and plan our treatment protocol.
There are usually two ways to treat a thymoma:
1. Surgical removal of the thymoma by means of a thoracotomy (opening up the chest cavity)
2. Radiation treatment to shrink the tumour to a level where it does not cause clinical disease

Due to Booboo's age, her dedicated owners decided to opt for radiation treatment.
Booboo underwent four general anaesthetics in an eight day period to allow her to receive four rounds of radiation treatment. Initial response to treatment has been excellent and the tumour has shrunk in size.

We expect to see Booboo back in a few weeks to repeat her CT scan and check on the progress of her tumour. Our hope is it remains a small size, so that it is many months/year before we see the return of any clinical signs. In the meantime, Booboo is enjoying life again and is back to her usual cheeky self.

This is the first time we have treated a thymoma in a rabbit in this way and, together with our Diagnostic Imaging and Oncology teams, we are all delighted with Booboo's progress.