Case of the Month – May 2018

Paloma is a robust two and half year old female guinea pig who lives with her sister Popcorn. She had a long standing history of ovarian cysts that had never caused any problems and was generally a very happy pig. Poor Paloma however then developed bladder stones, resulting in bloody urine and painful urination. Thankfully this was managed medically with pain relief, flushing of the stones under anaesthesia and a change in diet and increase in water intake to try and prevent further formation. However for poor Paloma her genitourinary system was not done with causing problems! On her regular checks it was noted that her cysts were increasing in size quite dramatically and her abdomen, despite pain relief and normal urination was still not comfortable. Now that these cyst were an issue it was decided to operate and neuter her. Ovarian cysts are nonfunctional, fluid-filled cysts that develop spontaneously near the ovaries throughout the female guinea pig’s reproductive cycle. These cysts can be associated with elevated hormones which can give clinical signs such as irregular cycles, infertility, persistent oestrus and hair loss. Potentially more serious uterine disorders can develop, as Paloma proved, with uterine cancer being reported in conjunction with the cysts. As you can see from the picture below – Paloma’s ovarian cysts were enormous! Measuring a whopping 3cm!! IMG 0161 Any female entire guinea pig can develop ovarian cysts and often they show no clinical signs. We don’t fully understand why these cysts form but age does seem to have a bearing with Hartley and Abyssinian breeds being slightly more prone. As you can see in the pictures not only did Paloma have enormous ovarian cysts she had also started to develop a uterine tumour. Lab results show it to be a smooth muscle form of cancer called a Leiomyosarcoma combined with cystic rate ovary and cystic mesonephric ducts! No doing things by halves here!! IMG 0162 Thankfully surgery is curative so we were all very relieved to give Paloma the good news and are pleased to report she is back to her old self! Permanent treatment of ovarian cysts requires surgery with a ovariohysterectomy commonly being perform. Some guinea pigs can respond to hormone injections and drainage of the cysts but this carries increased risks. If a female guinea pig is showing signs of ovarian cysts we will recommend neutering before other potential life threatening side effects occur. Tumors of smooth muscle, therefore can arise at any body site where there is smooth muscle; these are rarely reported in Guinea Pigs but major locations recognized in the Dog are the female reproductive tract, the digestive system or the spleen and/or liver. At the Barn we regularly neuter both male and female guinea pigs to prevent these problems and would recommend if you are not planning on breeding from your guinea pigs then neutering is the way forward.