Disseminated cutaneous mast cell tumor in a South American coati (Nasua nasua).

Cutaneous mast cell tumors have been described in all species of domestic mammals. However, information about these tumors in free-ranging and captive wild mammals is limited, with no reports in procyonids. This report aims to describe a case of disseminated cutaneous mast cell tumor in a captive South American coati (Nasua nasua). The animal was submitted to euthanasia and necropsy. On external examination, multiple papules, nodules, and plaques were distributed over the body surface. On cut section, they were soft and white. Histologically, they were composed of dense sheets of neoplastic cells interspersed with a delicate collagenous stroma. Cells were round and had a finely granular cytoplasm. Mast cell tumors were diagnosed based on histological features, positive staining with toluidine blue, and immunohistochemical labelling for the KIT protein. To the best of our knowledge, this is the first report of disseminated cutaneous mast cell tumor in this animal species.