What should you know about malignant melanoma in dogs?

In dogs, melanoma can arise in the mouth, nail bed, skin, or other pigment-producing tissue. A dark colour does not by itself prove that a lump is malignant; benign growths, inflammation, trauma, and other tumours can resemble it. Oral lesions may cause bad breath, drooling, difficulty chewing, facial swelling, or loose teeth. A nail-bed lesion may cause licking, swelling, or a damaged claw. The veterinarian may examine the growth, mouth, skin, and lymph nodes, then recommend a needle sample or biopsy. Laboratory review identifies the tumour type and provides information needed for treatment planning.

Arrange a veterinary appointment for a new, enlarging, bleeding, ulcerated, or irritated lump, especially in the mouth or around a nail. Photograph the area, record changes in appetite or behaviour, and prevent persistent licking or chewing if your veterinarian advises a protective collar. Do not squeeze, cut, or apply human creams to the growth. Further checks may include chest imaging, abdominal assessment, or sampling of nearby lymph nodes. Depending on location and findings, care may involve surgical excision, tumour removal surgery, radiation, or systemic treatment discussed by a veterinary oncology team.

Seek same-day veterinary help if your dog cannot eat or drink, has repeated bleeding, noisy or difficult breathing, marked facial swelling, severe pain, collapse, or sudden weakness. A newly noticed lump without these signs still warrants a timely appointment because surface appearance does not show whether disease has spread. After diagnosis, report persistent vomiting, seizures, breathing changes, extreme tiredness, or rapid loss of function without waiting for a routine review.

Ask where the tumour started, whether a biopsy is needed, what staging tests are appropriate, and whether nearby lymph nodes should be sampled. Discuss the aim of treatment, expected recovery, pain control, feeding support, warning signs at home, and how follow-up will monitor the mouth, skin, or nail area.