Conjunctival Melanoma

Melanoma is a malignant neoplasm of melanocytes and can develop on the conjunctiva of dogs and cats. Melanocytoma, a benign melanocytic tumor, occurs extremely rarely on the conjunctiva. Conjunctival melanoma is found most commonly on the conjunctiva of the third eyelid and next most commonly on the bulbar conjunctiva. It is locally aggressive and may metastasize. The neoplasm may be pigmented or nonpigmented (amelanotic melanoma). It occurs in middle-aged and older dogs. Purebred dogs are described as more susceptible, with Rottweilers and Cocker Spaniels somewhat more frequently represented.

Note: Melanocytoma, a benign tumor of melanocytes, occurs extremely rarely on the conjunctiva.

Treatment

Diagnosis is established by histopathologic examination of the neoplasm. Because of its metastatic potential, the regional lymph nodes should be evaluated by aspiration and radiography, MRI, and CT may be performed as part of staging. Surgical removal of the tumor is necessary. If the lesion is highly invasive, enucleation is performed.

Melanoma on the conjunctiva of the third eyelid. Aggressive local infiltration is evident and the neoplastic lesion involves the entire third eyelid. The lower eyelid laceration is an old lesion and is unrelated to the melanoma.

Very aggressive conjunctival melanoma in a German Shepherd Dog.

Adapted from the Atlas of Ocular Diseases in Dogs and Cats by Dr. Siniša D. Grozdanić and colleagues. © Animal Eye Consultants of Iowa. The text and clinical images on this page are original content from the authors' own clinical practice and research, and may not be reproduced, distributed, or repurposed without permission.

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