Eyelid Tumors in Dogs

Overview of Canine Eyelid Tumors

The eyelid is a common site of tumor formation in dogs. Most eyelid tumors occur in middle-aged to older animals. The vast majority of eyelid tumors in the dog are benign.

Canine eyelid tumors often originate spontaneously from the glands located within the eyelid margin. Complete surgical removal is the recommended treatment and is usually curative.

Eyelid tumor enlargement can interfere with proper eyelid blinking and cause ocular irritation from rubbing of the tumor against the cornea. Conjunctivitis and increased ocular discharge are common in animals with growing eyelid tumors.

Not all nodules or masses of the eyelids are tumors. Certain types of inflammation may also mimic the appearance of eyelid tumors.

What to Watch For

• Swelling and nodule or mass formation on the eyelid surface or along the eyelid margin
• Ulcerated and reddened area on eyelid margin
• Excessive tearing
• Mucoid or pus-like discharge from the eye
• Bloodshot or reddened conjunctiva
• Cloudiness, bluish haze or film covering the cornea
• Frequent pawing or rubbing of the eye
• Minor bleeding from the eyelid
• Increased blinking or squinting of the eyelids

Diagnosis of Eyelid Tumors on Dogs

Veterinary care includes diagnostic tests to determine the type of eyelid lesion and to direct subsequent treatment. Your veterinarian may recommend some of the following:

• Complete medical history and physical examination
• Complete ophthalmic examination including close examination of the eyelids, cornea, conjunctiva, and front chamber of the eye
• Fluorescein staining of the cornea
• Bacterial culture of secretions of the eye
• Fungal culture and cytology (microscopic examination) of skin scrapings from around the eyelid
• Fine needle aspirate of the eyelid tumor for cytology
• Tissue biopsy of the eyelid tumor
• Complete blood count and serum biochemistry
• Chest X-rays to look for possible spread of the tumor

Treatment of Eyelid Tumors on Dogs

Treatments for eyelid tumors may include one or more of the following:

• The recommended treatment for most canine eyelid tumors is surgical removal, using either a scalpel or laser. Complete excision is usually curative for the benign eyelid tumors.
• Large eyelid tumors may require surgical reconstructive techniques of the skin and tissues around the eyelid to preserve adequate protection of the eye after tumor removal.
• Certain types of eyelid tumors may respond to medical therapy if they are small and do not invade nearby tissues extensively. Small mast cell tumors (mastocytomas) may respond to systemic corticosteroids or locally injected corticosteroids. Lymphosarcoma of the eyelid may respond to chemotherapy, as this location of the tumor usually represents metastasis (spread) of systemic cancer from somewhere else in the body.
• Certain types of tumors may respond to cryotherapy, which is freezing of the tumor.
• If the tumor is large and invades the surrounding tissues, then surgical removal may also involve removal of the eye and permanent closure of the skin of the face and forehead.

Home Care and Prevention for Eyelid Tumors on Dogs

If an eyelid nodule or swelling is observed, call your veterinarian promptly. Immediate evaluation of the eyelid lesion is very important if accompanying symptoms of ocular discomfort are observed, such as increased blinking, tearing and redness of the eye.

Gently wipe away any eye discharge with a warm moist cloth as needed to keep the eyelid area clean. Do not allow the pet to rub or self-traumatize the eyelids. After diagnosis of an eyelid tumor, lubricating or antibiotic ointments may be prescribed until the time of surgical removal.

There is no preventive care for most types of eyelid tumors. It is well known that squamous cell carcinoma develops more commonly in dogs with pink or white eyelid margins that have prolonged sun exposure. Reducing sun exposure in these dogs by always allowing them shaded area may help to reduce the risk of developing this type of tumor.

Information In-depth for Canine Eyelid Tumors

The vast majority of eyelid tumors in the dog are benign. Malignant tumors tend to grow more rapidly than benign tumors and local invasion of surrounding tissues can be more extensive.

Canine eyelid tumors most often originate from the glands located within the eyelid margin. Sebaceous gland (meibomian) adenoma, squamous papilloma and benign melanocytoma represent the most commonly diagnosed eyelid tumors in the dog. Other less common benign tumors include the fibroma and histiocytoma. Complete surgical removal is usually curative for these tumors.

Malignant tumors that occur in the eyelid of dogs include the basal cell carcinoma, mast cell tumor, lymphosarcoma, malignant melanoma, squamous cell carcinoma, sebaceous adenocarcinoma (rare) and fibrosarcoma (rare).

The most important aspects of treating eyelid tumors are to determine the specific tumor type and the degree of local invasiveness and/or spread to other parts of the body. These two factors are essential to determine the most appropriate therapy for each animal.

A few other eyelid conditions can mimic the symptoms similar to those observed with eyelid tumors. It is important to exclude these conditions before establishing a conclusive diagnosis.

• Hordeolum (stye). Styes represent bacterial infections or inflammation of the eyelid margin glands. They can appear as either a single abscess or multiple abscesses with swelling along the eyelid margins.
• Chalazion. A chalazion is the retention and accumulation of material within one of the glands of the eyelid. Chalazia typically appear as smooth white, yellow or tan nodules along the inside rim of the eyelid margins. They may remain quiet and non-painful with little to no change in appearance, they may eventually decrease in size, or they may induce inflammation and increase in size.
• Allergic blepharitis (inflammation of the eyelids). Ocular exposure to a contact allergen can result in a rapid onset of symptoms that include eyelid (conjunctival) swelling and redness. The eyelid condition may also be associated with a generalized allergic reaction of the body. This is most often seen after insect bites, drug reactions and as a post-vaccination reaction.
• Autoimmune skin diseases. Certain autoimmune skin diseases can manifest as eyelid inflammation, swelling and ulceration. These include pemphigus foliaceus, pemphigus vulgaris, and pemphigus erythematosus. These diseases commonly affect the skin of the face, lips, nose pads, ears and eyelids.
• Bacterial blepharitis. Inflammation of the eyelids is often caused by Staphylococcus and Streptococcus spp. of bacteria infecting the meibomian glands located within the eyelid margin. Abscesses form nodules along the eyelid margin. The infections can be long-standing and recurrent in nature. In puppies, this condition can be quite severe and cause considerable facial and eyelid swelling.
• Parasitic blepharitis. Both demodectic and sarcoptic mange can involve the eyelids in dogs. In young dogs, the infection is commonly isolated to the face and eyelids. Typically these mites cause crusty, hairless lesions on the eyelids rather than nodule formation.
• Mycotic (fungal) blepharitis. Ringworm can cause inflammation of the eyelids, but usually cause hairless and crusty lesions rather than the development of nodules or masses.
• Cuterebra larvae. The Cuterebra fly may lay its eggs along the eyelid margin. After the eggs hatch, a large larval worm begins to grow under the skin and a slow growing mass may develop around it. The mass always has a small hole in the surface of the skin through which the larva breathes.
• Granulomatous inflammation. Certain immune-mediated inflammations of the eyelids of dogs may form nodules that appear very similar to eyelid tumors. These include two rather unusual diseases: nodular granulomatous episcleritis and periadnexal multinodular granulomatous dermatitis. Both of these conditions may be accompanied by nodules in other locations, such as within the eye or skin.

Diagnosis In-depth

Diagnostic tests are performed to determine the cause for the eyelid nodule/swelling, verify that the lesion is of a specific tumor type, define the degree of local invasion of the tumor, and determine if the eyelid tumor will spread. The following tests are often recommended:

• Complete medical history and physical examination including palpation of regional lymph nodes for evidence of enlargement and auscultation of the chest. Historically, it is important to ascertain the duration of the eyelid lesion, the occurrence of any prior tumors (anywhere in the body), and any accompanying physical symptoms of disease.
• Complete ophthalmic examination includes close examination of the eyelids, cornea, conjunctiva, and front chamber of the eye. This examination helps to delineate the boundaries and local extent of the eyelid tumor. The conjunctiva and cornea are examined for evidence of irritation caused by the eyelid tumor.
• Fluorescein staining of the cornea is performed to assess the presence of corneal erosions and ulcerations.
• Bacterial culture of secretions from the eye may be done to determine the presence and type of bacteria.
• Fungal culture and microscopic examination of skin scrapings from around the eyelid are done to assess for the presence of ringworm and parasitic mites.
• Fine needle aspirate of the eyelid tumor for cytology (complete cell analysis) can, in some cases, help to classify the type of tumor. Because cells are difficult to retrieve in some tumors, this test may be inconclusive.
• Tissue biopsy of the eyelid tumor provides the best means to establish a definitive diagnosis of the tumor type.
• Complete blood count and serum biochemistry are done to evaluate organ functions and to search for evidence of infection or certain types of malignant cancers such as lymphosarcoma.
• Cytology of cell aspirates from enlarged regional lymph nodes may be considered
  to assess for the presence of tumor metastasis.
• Thoracic (chest) and abdominal radiographs are performed to determine the presence and extent of tumors that are suspected to have spread from somewhere else in the body.

Treatment In-depth for Dogs with Eyelid Tumors

With respect to treatment eyelid tumors may be divided into two types, those that can be managed with medicines and those that require surgery. Most eyelid tumors in dogs require surgery, and the surgery may be followed by the application of certain topical medications.

In the early stages of eyelid tumor development, clinical evidence of eye discomfort or irritation is often not evident. Invariably, as eyelid tumors enlarge, they result in irritation to the surface of the eye and interfere with adequate blinking resulting in discharge from the eye. The irritation caused by enlarging eyelid tumors may be difficult to treat medically until the eyelid tumor can be treated and removed surgically.

Medical Management

• Certain types of eyelid tumors may respond to medical therapy, especially if the growth is small or too invasive to excise completely. Small mast cell tumors (mastocytomas) and certain histiocytomas may respond to systemic or locally injected corticosteroids.
• Lymphosarcoma (LSA) in the eyelid often represents metastatic (spread of the disease) from somewhere else in the body. In early stages of eyelid/conjunctival LSA, chemotherapy may reduce the size of the tumor regression and cause remission in some animals. However, response to chemotherapy is unpredictable and dependent on numerous factors.
• Response to medical therapy for all other eyelid tumors is poor. This is in contrast to some forms of inflammation of the eyelids, which often respond well to various medications.\

Surgical Management

• The recommended treatment for most canine eyelid tumors is surgical removal. This can be accomplished with either surgical excision using a scalpel or via laser surgery. Eyelid tumor removal with surgical excision is the preferred method for two reasons. First, the margins of the excised piece of tissue containing the tumor can be examined microscopically to ensure that they are free of tumor cells and that tumor excision was complete. Second, precise surgical closure of the eyelid incision is best accomplished with sutures.
• In contrast, laser therapy to remove eyelid tumors vaporizes the tumor, and a biopsy specimen cannot easily be obtained for examination. Surgical margins cannot be evaluated after laser therapy, and precise closure of the incision does not always occur, so there is greater scarring of the eyelid. Diode or carbon dioxide lasers can be used successfully to treat small eyelid tumors that ideally do not involve the eyelid margin, and are most effective on tumors that contain pigment.
• Complete excision of most benign eyelid tumors in the dog is usually curative.
• Extensive plastic and reconstructive surgery may be necessary following the removal of very large tumors. Maintaining a continuous eyelid margin and mobile upper eyelid are paramount to maintaining ocular health and vision. As a general guideline, eyelid margin tumors that involve greater than 1/3 of the total length of either the upper or lower eyelid prevent simple removal of the tumor and necessitate performing reconstructive surgeries. It is not uncommon for major reconstructive surgeries to be performed in stages, with at least two separate surgical events.
• Certain types of tumors may respond to cryotherapy, which is freezing of the tumor. This therapy may be considered for the benign meibomian gland tumors, benign melanocytomas, invasive histiocytomas, some small mast cell tumors, small and confined squamous cell carcinomas, and selected other tumors.
• Some eyelid tumors are too large or extensive to remove surgically, and enucleation or removal of the eye is necessary. Advanced eyelid tumors may extend into the soft tissues behind the eye (into the orbit) or into the eye.

Home Care for Dogs with Eyelid Tumors

Optimal treatment for your dog requires a combination of home and professional veterinary care. Most dogs are sent home wearing an Elizabethan collar to prevent self-trauma to the surgery site. Follow-up visits are important, especially if recurrence of the eyelid tumor is possible. Administer all prescribed medication as directed. Alert your veterinarian if you are experiencing problems treating your pet. If any signs of squinting or yellow-green infected discharge occur following the surgery, notify your veterinarian. Sutures are usually removed 10-12 days after the surgery.

The risk of recurrence or re-growth of eyelid tumors after surgical removal is a possibility for some of the malignant tumors. Fortunately in the dog, the majority of eyelid tumors are benign, and complete removal of the tumor prevents recurrence. Early diagnosis and prompt treatment result in the best outcome for all eyelid tumors. The chance of recurrence for malignant tumors depends upon the type of tumor, whether or not chemotherapy effectively caused decrease in size of the tumor, the stage of tumor development at the time of surgery, and whether or not the entire tumor could be surgically removed.