**3. Melanoma clinical signs and diagnosis**

Clinical signs of canine oral melanoma include halitosis, dysphagia, anorexia, weight loss, facial swelling or swelling of the lymph nodes, drooling, panting, loss of teeth, and oral and facial pain, which may induce the dog to avoid being touched. Dogs affected by oral melanoma can also be asymptomatic; in these cases, the owner or veterinarian may discover the oral mass only during routine examination. The owner may also notice blood in the water or food bowl or that oozing from the mouth [10–13].

The diagnostic methods include biopsy of the tumor, followed by histopathological examination. Immunohistochemical tests can provide a reliable and definitive diagnosis [7]. The diagnosis may be confirmed by cytology of a fine-needle aspirate [10]. Immunofluorescence can also be used to distinguish melanomas from melanocytomas [14]. However, other tests, such as skull radiographs, chest X-rays, mandibular lymph node samples, abdominal ultrasound, serum biochemistry, and complete blood count, are crucial for a better patient health overview, metastasis detection, and safer treatment choice [15].
