Alex Civello: Crumble’s eye tumour
Veterinary pathology has a key role in the diagnosis of diseases in animals. Alex Civello is a veterinary pathologist working in a private laboratory that specialises in veterinary ocular pathology. He sees eye cases from a wide range of species, and here he describes a case from a dog called Crumble.
Alex Civello: finding and treating the cause
Crumble is a Lhasa Apso dog. Her owner took her to the vet because one of her eyes looked red and sore. The vet could see that there was a tumour in the back of the eye. There was also increased fluid pressure inside the eye (glaucoma). This was detected with a test using a tonometer, a handheld ‘pen’ that is used to make momentary contact with the cornea.
There was bleeding inside the eye and Crumble had no vision from it – the vet decided it was impossible to save it. The vet opted to surgically remove the eye, and the eye was sent to us in the laboratory for diagnosis.
When I dissected the eye, I could see the tumour and the bleeding into the eyeball that it had been causing. I examined the tumour under the microscope and diagnosed it as an iridociliary adenoma. These are the second most common tumours to arise in the eyes of dogs, after melanoma, which is the most common. They usually occur in older dogs. Fortunately, they are benign and do not spread to other parts of the body via the blood. I could advise the vet that Crumble was cured of her tumour, and there is no increased risk of the other eye developing glaucoma or becoming blind.
There are many eye conditions that can have consequences for the other eye or the dog’s overall health. In Crumble’s case it was good news that this was a benign tumour and she was cured by the surgery she had. Sometimes, malignant tumours (ones that are cancerous) can arise in or spread to the eye from other organs in the body, before being detected anywhere else. Getting a rapid pathological diagnosis directs the vet towards appropriate further investigation and, in many cases, treatment, such as surgery or chemotherapy.
Glaucoma in dogs
When glaucoma is caused by another problem in the eye, such as inflammation or a tumour, it is known as secondary glaucoma. Dogs can also develop forms of inherited primary glaucoma. The main problem with primary glaucoma is that it usually affects both eyes, although commonly not at the same time. Therefore, if it is diagnosed, the vet will know to monitor the other eye closely and may decide to use eye drops to try to delay the onset.
Certain breeds of dog are more likely to develop primary glaucoma; there are screening programmes for glaucoma and other hereditary eye disease in dogs to help inform a decision on whether a certain dog should be used for breeding.