Figure 3: Massive, follicular/retention ovarian cyst, and mammary tumors in 2.6-year-old intact female rat (Charlotte).
Case history and photos

History

Charlotte is a 2.6-year-old intact, silver fawn, female rat, weighing 333g. She is housed with her cagemate and best friend, Cassidy. Charlotte was adopted at 18 months of age. At the time, she had not been handled and would bite. After much socializing, she can now be handled by her keeper without being bitten. However, Charlotte dislikes handling very much and it causes her a lot of stress.
(Note that Charlotte’s keeper is also her veterinarian.)

Clinical signs

Charlotte’s keeper discovered a caudal mass.

Diagnosis

The caudal mass was diagnosed to be a mammary tumor.

Treatment

Normally, at Charlotte’s age, her veterinarian would have opted for medical management (e.g., Tamoxifen, bromocriptine). However, due to the stress daily medication would cause Charlotte, as well as that she is very fit for her age, the decision was made to remove the tumor instead.

While Charlotte was under general anesthetic (sevo/O2) two smaller mammary tumors were discovered on the same side as the larger one. Her veterinarian also noticed dried foul-smelling discharge around her vulva and tail base, indicative of pyometra, and the decision was made to perform an ovariohysterectomy as well, although this had initially not been planned due to Charlotte’s age. A massive follicular/retention cyst was discovered on the right ovary; this was probably the cause of the pyometra.

Charlotte received meloxicam pre-op and buprenorphine on recovery.
Meloxicam was continued post-op for 5-7 days.

Outcome

Charlotte is recovering well. She remained with her cagemate, Cassidy, throughout her recovery period and both rejoined the Mischief 7 days later.

Photos

Case history and photos courtesy of Adele Wharton, BVSc, MRCVS, CertGP (F&L)