| Eyelid neoplasms are the most frequent group of ophthalmic neoplasms in dogs. Adenoma and adenocarcinoma of the meibomian gland are the most common lid neoplasms (~60%); local disfigurement and irritation necessitate local excision, which is usually successful. Sebaceous adenocarcinomas are locally invasive and histologically malignant but are not known to metastasize. Lid melanomas, exhibited as spreading pigmented masses on the eyelid margins, should be widely excised. Other
frequent eyelid neoplasms include histiocytoma, mastocytoma, and papilloma. |
| Orbital neoplasms in dogs produce exophthalmia, conjunctival and eyelid swelling, strabismus, and exposure keratitis. The globe cannot be retropulsed. Usually, there is no pain. Because ~90% of the neoplasms are malignant and ~75% arise within the orbit, the prognosis for longterm survival is often poor. The neoplasm type should be determined histologically, and the extent of the mass determined by physical examination, skull radiographs (including special contrast procedures,
computed tomography, and MRI), and ultrasonography before treatment by surgical excision or radiation. Excision of the orbital mass with the globe and all orbital tissues (including adjacent bone) may decrease the possibility of recurrence.
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Corneal and limbal neoplasms are uncommon in dogs and can be confused with nodular fasciitis and proliferative keratoconjunctivitis in Collies. Limbal or epibulbar malignant melanomas are focal, usually superficial, pigmented masses that extend both onto the cornea and caudally toward the globe’s equator. After close intraocular examination, including gonioscopy and B-scan ultrasonography, to detect possible penetration of the sclera, partial- to
full-thickness surgical excision with scleral grafts, cryotherapy, or laser photocoagulation is usually successful. If intraocular extension occurs, enucleation is performed. |
| Malignant melanomas are the most common uveal neoplasm, are usually pigmented, and most frequently involve the iris and ciliary body. Clinical signs of anterior uveal melanomas may include an obvious mass, persistent iridocyclitis, hyphema, glaucoma, and pain. Ciliary body adenoma and adenocarcinoma are the most frequent epithelial neoplasms of the anterior uvea. Signs may include hyphema, glaucoma, and usually a nonpigmented mass behind the iris and in the pupil. Neoplasms of
neuroectodermal origin are rare. Treatment is usually enucleation. Recent studies in iridal melanomas, especially in Labrador Retrievers, suggest noninvasive diode laser photocoagulation may be effective and can be repeated if necessary. Secondary uveal adenocarcinomas are relatively infrequent and originate from a number of distant sites. Other neoplasms such as the transmissible venereal tumor and hemangiosarcoma may metastasize to the anterior uvea. Lymphosarcoma frequently
involves the anterior uvea and other ocular structures, and may present as bilateral disease. Systemic therapy with topical and/or systemic anti-inflammatory treatment for intraocular lymphoma may be attempted using one of several available lymphoma protocols (eg, Madison, WI or Animal Medical Center: combination of cyclophosphamide, prednisolone, vincristine, and/or doxorubicin), but dogs with intraocular lymphoma have shorter survival times.
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