A Dog's Eyelid Anatomy
Your dog has upper and lower eyelids. However, eyelashes only appear on the upper eyelid. Several muscles help to cover and protect the eye (globe), and control the opening and closing of the eyelids. Pink conjunctiva lines the inner surface of the eyelid.
Externally, you'll find hair on the part of the eyelid that's farthest from the eye. There's a distinct line near the opening of the eyelid where the eyelid's outer surface transitions to smooth, pigmented skin.
This area is the eyelid margin, and it reaches the entire distance around the eyelid opening. The eyelid margin should rest smoothly against the surface of the cornea (the eye's clear surface).
Eyelids should close completely to protect the eye, wipe away dust, and spread tears evenly across the eye.
Many types of cells make up the eyelids and surrounding tissues. For example, meibomian glands are tiny glands at the edges of the eyelids. The openings of the Meibomian glands appear as a series of pinpoint dots. These glands contain cells that produce oily secretions that lubricate the eye.
As we define eyelid tumors and how these conditions can affect the eye, it's important to remember this anatomy. Understanding the types of cells contained in the eyelid can help you gain insight into the types of tumors that can develop in a dog's eyelid.
What types of eyelid tumors affect the eyelids?
A dog's eyelid is an extension of its skin. Therefore, the types of tumors that can develop in the skin can also develop in the eyelid.
Eyelid tumors in dogs are usually benign (non-cancerous). Benign eyelid tumors are common in middle-aged and older dogs. There are a few different types of eyelid tumors in dogs, including:
Benign Tumors
These are benign (non-cancerous) tumors that can develop in a dog's eyelid:
Meibomian Gland Adenomas
It's possible for these cells to over-multiply and develop into benign tumors called meibomian gland adenomas (non-cancerous), the most common eyelid tumor diagnosed in older dogs. There are also meibomian gland adenocarcinomas, a less common malignant (cancerous) tumor.
Meibomian gland adenomas may initially start as a small, smooth mass that emerges from the opening of a meibomian gland. However, over time the tumor may develop into a large mass with an irregular surface.
Even eyelid tumors that are technically malignant may sometimes still act benignly.
Papilloma
Viral papillomas (those caused by the papilloma virus) tend to appear in young dogs. These growths look like warts and tend to have a cobblestone appearance. They may be pink, white, or pigmented.
Dogs may have more than one papilloma at once, and they may develop around the eyes and in the mouth at the same time. Papillomas will sometimes (not always) disappear on their own.
Malignant Tumors
These eyelid tumors are malignant (cancerous):
Melanomas
Melanocytes are cells at the edges of the eyelids that produce pigment. These cells can also over-multiply and cause melanoma tumors. Melanomas in thi slocation are typically flat, brown-to-black masses that expand outward.
Alternatively, melanomas can also develop on the haired skin of the eyelid. These melanomas tend to be a single, round, darkly pigmented mass on the eyelid itself, as opposed to the eyelid margin.
Squamous Cell Carcinomas
This type of tumor is caused by the over-multiplication of skin cells (squamous) and is rare in dogs. These malignant skin cell tumors often have an ulcerated appearance and are more commonly found on areas of the eyelid that lack pigment.
Lymphomas or Mast Cell Tumors
Lymphoid tissue cells in the conjunctiva may over-multiply and cause lymphomas or malignant mast cell tumors. They emerge from mast cells, which are immune system cells that typically contribute to allergic reactions.
Mast cell tumors can be hard to recognize, and may or may not have pigment. They can grow rapidly and spread (metastasize), which makes them more challenging to treat.
Hystiocytoma
Another eyelid tymor that tends to impact young dogs is the histiocytoma. These tumors of Langerhands cells (immune system cells in the skin) tend to develop quickly. They are benign and often look like red, hairless, round buttons.
While a histiocytoma may develop anywhere on a dog's body, they are more common on the head, face, and front end.
While other types of tumors can affect the eyelids, conjunctiva, and periocular tissues, these are the most commonly diagnosed tumors.
What are symptoms of eyelid tumors in dogs?
The appearance of the tumor is sometimes the first symptom you'll see. However, a dog may also display eye-related symptoms that cause you to take a closer look at the eyelid and discover the mass.
Common symptoms of eyelid tumors in dogs include:
- Visible growths
- Redness in the eye
- Excessive or colored discharge from the eye
- Bleeding from the mass
- Squinting or holding the eye closed (ie. blepharospasm)
- Swelling in the eye
- Signs of ulceration
- Rubbing the face
- Eyelid pigmentation and/or cloudiness in the eye
- Distorted eyelid margin
- Tearing
- Being unable to fully close the eyelids
These symptoms may be related to irritation due to the mass. It's also possible the mass or tumor in your dog's eye may be an incidental issue and that your pup has a different underlying eye problem.
What causes eyelid tumors in dogs?
Tumors typically develop due to abnormal growth and unregulated replication of cells that make up the body's tissues. However, it's not clear why dogs develop the types of tumors listed above. Very few cancerous tumors are triggered by a single cause.
A complex combination of environmental, genetic, or hereditary risk factors may contribute to the development of these tumors.
Squamous cell carcinoma has been attributed to exposure to sunlight and ultraviolet rays. Dog breeds with light-colored coats and hairless breeds are particularly at risk. Otherwise, the causes of these types of tumors are unclear.
What should I do about my dog's eyelid mass or tumor?
Consult your veterinary ophthalmologist if you've noticed any of the symptoms listed above in your dog.
Even benign masses on the eyelid can distort the eye and be very painful. They can cause obvious discomfort and lead to significant issues, such as scarring or infection (if a dog keeps scratching at it) and obstruction of the tear ducts that produce tears. This may cause your pet discomfort, and eventually vision impairment.
How are eyelid tumors in dogs diagnosed?
Our veterinary ophthalmologists can partner with your primary veterinarian to provide the most comprehensive and compassionate eye care for your dog. When you bring your dog to our veterinary ophthalmologists, they may:
- Conduct a thorough exam of your dog. This exam will include vision testing, slit lamp examination (biomicroscopy), and indirect ophthalmoscopy.
- Ask about your dog's health history - when you noticed the symptoms and/or mass, how the symptoms or mast might have changed over time, etc.
- Carefully examine the eyelid along with the eye itself. They may need to use fluorescein stain to evaluate eye pressures, measure diameter of the mass, check for corneal ulceration secondary to the mass rubbing the cornea, and measure tear production in the eye
- Take a tissue biopsy of the tumor
- Test bacterial or fungal culture from the mass
- Take a cytology of skin scrapings around the eyelid
- Perform any blood work that may be required to gain insight into your dog's overall health in preparation for surgery.
- Take X-rays of the chest to find out if the tumor has spread.
What factors will my vet consider when planning treatment for my dog's eyelid tumor?
If your veterinarian has diagnosed your dog with an eyelid tumor, they'll likely consider these factors when planning the type and timing of your pet's treatment:
- The number of growths
- Size of the mass
- Duration of the problem and how fast the tumor is growing
- Location of the base of the mass (i.e. eyelid margin, middle layer of the skin, or conjunctiva)
- Your dog's ability to blink fully (to determine if lubricant is needed to protect the cornea)
- Your dog's age
- Evidence of irritation around the eyelid (e.g. bleeding, ulceration of the dermis, conjunctival hyperemia, ocular discharge, corneal ulcers, corneal vascularization)
- Evidence of the tumor spreading to lymph nodes or elsewhere (pointing to a need to stage the neoplasia before planning surgery)
What are treatment options for eyelid tumors in dogs?
Since there are no at-home or homeopathic remedies for this condition, eyelid tumor removal surgery (or blepharoplasty - the technical term for eyelid surgery) is generally the best treatment option.
After your veterinary ophthalmologist has examined your dog's eye and eyelid tumor or mass, they will work with you to create a treatment plan.
An effective treatment plan will address both the mass and any secondary issues that have developed as a result.
The goal will be to have the eyelids lie flat against the eye and close completely, so they'll be able to protect the eyes.
There are limits on how much of the eyelid can be surgically removed without compromising function, so early diagnosis and treatment while the mass is small are key.
To improve the chances of being able to completely remove the mass without jeopardizing eyelid function, a vet will typically recommend removing any eyelid mass that is larger than two or three milimeters.
Eyelid Tumor Removal Surgery in Dogs
When it comes to eyelid surgeries for dogs, tumor removal procedures are relatively common. Your veterinary ophthalmologist may recommend one of these eyelid surgeries to remove your dog's tumor:
Laser Ablation Surgery - Safe and effective, laser surgery to remove the mass can reduce or eliminate pain, bleeding and swelling.
Wedge Resection - This surgery is used to treat a tumor that takes up less than 30% of the length of the eyelid. During the procedure, the vet will remove a small wedge of the eyelid, and the tumor itself. A special suture pattern will be used to line up the eyelid margin again and close the seam.
Cryotherapy (Debulking) - Smaller tumors sometimes respond well to this treatment, which involves freezing the affected tissue with liquid nitrogen so it falls off.
V-Plasty Surgery - This outpatient surgical option is recommended for larger benign and malignant growths. During a V-plasty surgery, your veterinarian will remove a small wedge of tissue where the growth is located, then stitch the incision back together using sutures.
Enucleation - Very rarely, enucleation may be recommended for cancerous eye tumors. This surgery may be the last resort if a significant amount of tissue must be removed to ensure the cancer is gone.
Some smaller benign tumors disappear or fall off on their own. Conversely, more aggressive treatment options include chemotherapy and radiation may be recommended for cancerous masses.
Reconstructive surgery may also be needed following the excision. A second eyelid surgery may be required if your dog's tumor returns. If a mass regrows, you will notice an elevated, usually smooth, bump that protrudes from the surgical site.
How much will my dog's eyelid tumor removal surgery cost?
A number of factors contribute to the cost of an eyelid tumor removal surgery for a dog. These include diagnostic tests that may be needed, pre-and post-operative evaluations, medications, anesthetic and more.
Your veterinary opthalmologist at Northwest Animal Eye Specialists can provide an accurate cost estimate of. your dog's procedure.
What will my dog's prognosis be after surgery to remove the eyelid tumor?
Following surgical removal of a tumor from a dog's eyelid, the prognosis is usually positive and the risk of recurrence is relatively low. If a tumor returns, it generally happens within six months. During this period, it will be important to check the area regularly and schedule followup visits with your veterinary ophthalmologist and veterinarian.
Your Dog's Recovery From Eyelid Tumor Removal Surgery
Post-operative care at home will be important to help your dog recover. If your dog rips sutures out or the area becomes irritated, this can delay healing or cause the eyelid to become permanently disfigured.
Your veterinary ophthalmologist may provide specific post-op instructions, including:
- Cleaning the surgical site with a warm washcloth daily to remove any debris
- Applying lubricating or antibiotic ointment to the affected eye on a daily basis
- Administering medications to control pain and inflammation
- Using an Elizabethan collar to protect the area and prevent your dog from rubbing or scratching the surgical site
- Keeping your dog from doing too much physical activity, or playfighting with other pets
Your veterinary ophthalmologist will likely recommend an Elizabethan collar to protect the area. They may also recommend using lubricating agents to keep the area moist. Some dogs may need radiation or chemotherapy for malignant tumors.
Note: Northwest Animal Eye Specialists specializes in treating eye conditions and illnesses. The advice provided in this post is intended for informational purposes and does not constitute medical or behavioral advice regarding pets. Please make an appointment with your vet for an accurate diagnosis of your pet's condition.