Eyelid Tumors in Cats
Dr. Noelle McNabb
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 incidence 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 check for 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 can be done to assess the presence of ringworm and parasitic mites.
Fine needle aspirate of the eyelid tumor for cytology (complete cell analysis) can help to classify the type of tumor in some cases. Because cells are difficult to retrieve from some tumors, this test may be inconclusive. In such instances a tissue biopsy is needed to reach a diagnosis.
Tissue biopsy of the eyelid tumor is the definitive way to establish a diagnosis of the tumor type.
Complete blood count and serum biochemistry can evaluate other organ functions and search for evidence of infection or certain types of malignant cancers such as lymphosarcoma.
Feline leukemia virus (FeLV) and feline immunodeficiency virus (FIV) testing may be recommended. Cats positive for FeLV are at increased risk for developing lymphosarcoma. Cats that are FIV positive are at increased risk for spontaneous tumor formation and infections.
Cytology of cell aspirates from enlarged regional lymph nodes may be considered to assess for the presence of tumor spread or metastasis.
Thoracic (chest) and abdominal radiographs are performed to determine the presence and extent of tumors that are suspected to be metastatic.
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 cats 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. The ocular irritation caused by enlarging eyelid tumors may be difficult to treat medically until the eyelid tumor can be treated and removed surgically.
Certain types of eyelid tumors may respond to medical therapy, particularly if they are small and have not invaded nearby tissues. Small mast cell tumors (mastocytomas) may respond to systemic or locally injected corticosteroids.
Lymphosarcoma (LSA) in the eyelid often represents spread (metastatic disease) of the cancer from somewhere else in the body. In early stages of eyelid/conjunctival LSA, chemotherapy may reduce the size of the tumor and result in 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.
The recommended treatment for many eyelid tumors in the cat is surgical removal. This can be often be accomplished by removing a portion of the eyelid along with the tumor and then suturing the remaining eyelid back together. The tissue is then submitted for biopsy examination.
Complete excision of some eyelid tumors in the cat is curative. Some eyelid tumors invade nearby tissue microscopically and may recur following surgery. Other new tumors may also develop in the same or opposite eye. These new tumors typically do not represent spread of disease, but rather spontaneous development of new lesions.
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 eye 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 that involve the skin of the face and neck to be undertaken in stages; often with at least two separate surgeries.
Certain types of tumors may respond to cryotherapy, which is freezing of the tumor. This therapy may be considered for 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.