MTs are prevalent in dogs, representing the most frequent oral malignancy, compared to cats, in which ocular melanomas predominate. This study investigates the canine and feline MT epidemiology (2005–2024) of cases submitted to the Veterinary Pathology Service (University of Perugia). Among the canine neoplasms, 845 (4%) were melanocytic: 329 (39%) melanocytomas; 512 (61%) melanomas. Of these, 485 (57%) were cutaneous (4% of canine cutaneous neoplasms), 193 (23%) were oral (50% of oral canine neoplasms), and 104 (12%) were mucocutaneous. The average age of affected dogs was 10 years. Older dogs were more likely to have melanomas compared to melanocytomas (p < 0.001). There were 60 (1%) feline MTs: 6 (10%) melanocytomas; 53 (88%) melanomas. Of these, 29 (48%) were cutaneous (1% of feline cutaneous tumors), 18 (30%) were ocular, and 9 (15%) were oral (22% of feline oral tumors). The average age of affected cats was 11 years. In dogs, mucocutaneous melanomas were more common compared to cutaneous ones (p < 0.05); oral melanomas were more common compared to all other sites (p < 0.001). In cats, ocular melanomas were more common compared to cutaneous ones (p < 0.05). Our study provides the MT prevalence in a selected canine and feline population, revealing MT epidemiological patterns, highlighting species-specific differences in the tumor prevalence, localization, and age distribution.

Background: Melanoblasts originate in the neural crest from where they migrate to peripheral tissues and differentiate into melanocytes. Alteration during melanocyte development and life can cause different diseases, ranging from pigmentary disorders and decreased visual and auditory functions, to tumours such as melanoma. Location and phenotypical features of melanocytes have been characterised in different species, yet data on dogs are lacking.Objective: This study investigates the expression of melanocytic markers Melan A, PNL2, TRP1, TRP2, SOX‐10 and MITF in melanocytes of selected cutaneous and mucosal surfaces of dogs.Animals: At necropsy, samples from five dogs were harvested from oral mucosa, mucocutaneous junction, eyelid, nose and haired skin (abdomen, back, pinna, head).Materials and Methods: Immunohistochemical and immunofluorescence analyses were performed to assess marker expression.Results: Results showed variable expression of melanocytic markers in different anatomical sites, particularly within epidermis of haired skin and dermal melanocytes. Melan A and SOX‐10 were the most specific and sensitive melanocytic markers. PNL2 was less sensitive, while TRP1 and TRP2 were seldomly expressed by intraepidermal melanocytes in haired skin. MITF had a good sensitivity, yet the expression often was weak.Conclusions and Clinical Relevance: Our results indicate a variable expression of melanocytic markers in different sites, suggesting the presence of subpopulations of melanocytes. These preliminary results pave the way to understanding the pathogenetic mechanisms involved in degenerative melanocytic disorders and melanoma. Furthermore, the possible different expression of melanocyte markers in different anatomical sites could influence their sensitivity and specificity when used for diagnostic purposes.

Red foxes are widespread carnivorans acting as reservoirs of Babesia vulpes , which is highly prevalent in foxes, yet its clinical impact remains poorly understood. The description of Babesia banethi raised knowledge gaps regarding pathogenicity and life cycle. This study investigated the occurrence of Babesia spp. in red foxes from southern Italy. Overall, 54 red foxes were clinically examined, sampled for hemato-biochemical analyses, and screened for Babesia spp. using microscopy and PCR. Necropsies were performed on 20 animals. Ticks were collected, identified, and dissected for cytological detection of Babesia spp., as well as by PCR. Overall, 46.3 % of foxes tested positive for Babesia spp., with B. vulpes (42.6 %) predominating and B. banethi detected in two animals. Blood smear concordance with PCR was high, and morphometric differences between B. vulpes and B. banethi were evident. Most infected foxes were young and had clinico-pathological alterations, although trauma-related comorbidities limited interpretation. Two B. banethi–positive foxes had clinical babesiosis, suggesting pathogenic potential. In necropsied foxes, Babesia DNA was most frequently detected in the brain and merozoites were observed in cerebral capillaries. Of 67 ticks collected, five species were identified, including Ixodes kaiseri, firstly reported in Italy. No Babesia stages were observed in tick organs, but B. banethi DNA was detected in one I. kaiseri. This study documents a high rate of B. vulpes infection and the sympatric presence of B. banethi in southern Italy. It represents the first clinico-epidemiological, hematological, cytological and molecular examination of Babesia spp. in live foxes. The detection of B. vulpes in brain enhances our understanding of parasite tropism, while the presence of B. banethi in I. kaiseri raises questions about transmission routes. These findings highlight the importance of surveilling fox populations and ticks, given the increasing reports of B. vulpes infection in dogs and the potential spillover at the wildlife–domestic interface.

Oral melanomas are the most common oral malignancies in dogs and are characterized by an aggressive nature, invasiveness, and poor prognosis. With biological and genetic similarities to human oral melanomas, they serve as a valuable spontaneous comparative model. Primary cell cultures are widely used in human medicine and, more recently, in veterinary medicine to study tumorigenesis, cancer progression, and innovative therapeutic approaches. This study aims to establish two- and three-dimensional primary cell lines from oral canine melanomas using fine-needle aspiration as a minimally invasive sampling method. For this study, samples were collected from six dogs, represented by four primary oral melanomas and five lymph nodal metastases. The cells were digested to obtain single-cell suspensions, seeded in flasks, or processed with Matrigel^® to form organoids. The cell cultures were characterized through flow cytometry using antibodies against Melan-A, PNL2, and Sox-10. This technique offers a minimally invasive means to obtain cell samples, particularly beneficial for patients that are ineligible for surgical procedures, and enables the establishment of in vitro models crucial for comparative studies in mucosal melanoma oncology. To the best of our knowledge, this is the first work establishing neoplastic primary cell cultures via fine-needle aspiration in dogs.