Tumor of the Eye in Dogs

Tumors or growths found in the eye of our canine friends is not an uncommon case for those in the veterinary field. Tissue changes in the eye can develop as a primary tumor, and can also be a secondary result of spreading tumor cells that began in another part of the body.Tumors of the eye can be both malignant and benign.

Tumor of the eye in dogs can also be described as ocular neoplasia. New, abnormal growth of tissue in the canine eye can comprise of lesions found in the areas of the eyelid, cornea, conjunctiva, orbit, and other structural sections of the eye such as the iris or ciliary body.

Because of the number of eye tumors in existence, symptoms will vary from one type to another. Some of the lesions and their symptoms are listed here.

• Eyelid neoplasia
• This presents as a mass on the eyelid margin or within the lid
• It can range in color from pink to very dark brown
• Uveal melanoma
• There may be a mass on the iris or ciliary body
• The mass can protrude or distort the pupil
• Blood vessels can rupture
• There may be pain
• Later stages can include hemorrhage, retinal detachment or glaucoma
• Limbal (epibulbar) melanoma
• This tumor can be seen as mainly circular, pigmented masses on the cornea which point inward towards the globe of the eye
• There may be excessive tear production
• Often conjunctival irritation occurs
• Corneal squamous cell carcinoma
• This tumor will be characterized by a pink mass on the epithelial surface of the cornea
• The conjunctiva, eyelid, cornea and third eyelid are affected
• Orbital neoplasia
• The eyelid may protrude forward
• There can be swelling of the conjunctiva, cornea, and eyelid
• Often the two eyes do not move in tandem
• The pupil may be dilated

Types

There are multiple types of tumors that can grow in the eyes of our canine family members. Some of them are listed below.

• Eyelid neoplasia
• These tumors can be disfiguring and irritating
• They are usually slow growing
• Maintaining eyelid function is a concern during surgery
• The metastatic spread is low
• Weimaraners and Vizslas are known to be highly documented with this tumor
• Uveal melanoma
• This is most commonly seen in the Labrador Retriever
• This type of tumor can be both benign or malignant
• The tumor arises from the iris or ciliary body of the eye
• Limbal (epibulbar) melanoma
• Female dogs, German Shepherds, and Labrador Retrievers are documented to be predisposed
• The average age of a canine with this type of tumor is 5 to 6 years old
• The tumors are often benign
• Corneal Squamous Cell Carcinoma
• These tumors tend to be malignant
• Conjunctival neoplasia is included in this category
• After removal, the growth will often recur
• The lesions are known to be aggressive
• Orbital neoplasia
• 90% of these tumors become malignant by the time they are noticed
• They can invade the sinuses, oral cavity, bones, and brain
• They are generally nonpainful but the prognosis is poor

Though the exact causes of cancer have not yet been defined, your dog may get a tumor in the eye as a result of the following factors.

• There could be a viral cause
• UV light exposure may contribute
• A lesion may arise from the sebaceous gland at the rim of the eyelid
• Chronic ocular inflammation could be a factor
• Another metastatic disease could spread to the eye
• Brachycephalic breeds who have had recurring keratoconjunctivitis are susceptible to tumors

The eye may be a small part of the body, but the intricacy of the eye structure is complex. Because of this, your veterinarian will utilize many diagnostic tools when determining the cause of a tumor in your pet’s eye. Depending on the type of lesion, the location of the mass, and the suspected diagnosis, your veterinary caregiver will include many of the following means in order to come to a conclusion. She may also suggest a visit with the ophthalmologist for testing and imaging.

• A complete blood count and serum chemistry profile will be useful to analyze your dog’s health
• An veterinary ophthalmology specialist may do ocular tests that will consist of tonometry (to verify intraocular pressure), slit lamp (to look at structures at the front of the eye), and fundoscopy (to look at the interior lining of the eyeball)
• A gonioscopy will give an excellent view of the inner eye
• A physical examination will involve a thoracic auscultation, abdominal palpation, and analysis of regional lymph nodes to check for additional masses or swelling
• Radiographs of the skull, chest, and abdomen will determine if metastatic spread has taken place
• An ultrasound may rule out metastatic development, a computerized tomography (CT)scan can see bone involvement, and a magnetic resonance imaging (MRI) will check for soft tissue damage
• A fine needle aspiration or biopsy will also determine if tissues have been affected
• Your veterinarian or ophthalmologist will also look for secondary complications such as blindness or uveitis

Treatment of a tumor of the eye will be contingent on the type of mass. For example, lid tumors might be removed surgically by excision, taking care to remove all of the mass while trying to maintain a well functioning eyelid. Cryosurgery, which is using extreme cold to kill affected tissue, is another method.

Tumors such as uveal melanoma can mean the loss of the eyeball, but sometimes laser surgery is successful without taking the eye out. Limbal melanoma could mean a keratectomy or sclerectomy, which is surgical removal of the lesion, with the added step of graft replacement.

In the case of a corneal tumor, if superficial, the tumor alone might be excised. If the complete eyeball is affected, it will need to be removed. Orbital lesions might necessitate removal of the entire eyeball, along with nearby bone and tissue if there is involvement.

Enucleation is a procedure whereby the globe of the eye is taken out while preserving the soft tissue. This is possible in many cases.

In cases where the tumor was found to be malignant, and there has been an advance to other tissues, radiation and chemotherapy will be part of the recovery process. If the tumor was impossible to remove, palliative care would be the best way to give your beloved furry family member a good quality to the remainder of his life.

Fortunately, the prognosis for tumors in the eye is often positive. Follow up with your veterinary caregiver will be needed for perhaps a period of a few months. Immediately upon your arrival home from the eye surgery, you will need to be aware of the possibility of swelling, and be able to put eye drops or antibiotic cream in the eye if required. Be certain to wash your hands whenever you apply medications or ointments to your dog’s eye area.

If you have any concerns, contact your veterinarian or specialist directly. It must be noted that regrowth of certain tumors of the eye frequently materializes.