Canine Melanoma Symptoms

Melanoma is a tumor (lesion) that grows out of skin cells. Canine melanoma symptoms depend on the type of melanoma. Melanoma in dogs comes in three main types. Cutaneous melanoma occurs on the skin, usually as a single growth, most commonly on the face, feet or scrotum. Oral melanoma occurs in the mouth. Uveal or intra-ocular melanoma occurs in the eye.


Each of the three types of melanoma can be malignant (cancerous) or benign. The technical name for a benign melanoma is a melanocytoma. Malignant melanoma usually grows fast and can kill a dog by spreading into other parts of the body through the lymphatic system. So if you notice lesions on your dog, consult a vet for a proper diagnosis.

  1. Cutaneous Melanoma

    • Melanomas on a dog's skin usually initially appear as a small lesion that grows if left untreated. Melanoma lesions may be pigmented (dark or black) or unpigmented. Often, a cutaneous melanoma does not have other initial symptoms, unless it occurs in the nail bed or on the foot pads where it can cause diffuse swelling that can lead to lameness.

      If the melanoma is malignant and spreads to other parts of the body, symptoms vary based on which organ the cancer has infected. For example, a melanoma that spreads to the lungs can cause respiratory problems. According to PetPlace.com, 20 to 50 percent of cutaneous canine melanomas are malignant.

    Eye Melanoma

    • Melanoma in the eye usually initially appears as a small lesion. According to the National Canine Cancer Foundation, most eye melanomas are darkly pigmented, and if an eye melanoma is pink, it has a high risk of being malignant. Although melanoma in the eye does not initially cause other symptoms or affect vision, as the melanoma grows, it can cause glaucoma, detached retina or blindness.

    Oral Melanoma

    • Melanoma in the mouth usually initially appears as a small lesion that may be pigmented (dark or black) or unpigmented. Dogs with oral melanoma may develop bad breath, loose teeth, bleeding from the mouth, drooling, swelling in the face or trouble eating, leading to weight loss. According to the National Canine Cancer Foundation, melanomas in the mouth have a higher risk of being malignant and spreading to other parts of the body.