RESUMO
Case summary: This report describes the case of a 7-year-old male neutered domestic mixed-breed cat that was initially referred to the Veterinary Hospital of the State University of Londrina for evaluation of a 2-week history of abdominal distension and a 2-day history of anorexia, infected with feline immunodeficiency virus (FIV). Abdominal ultrasound revealed an expansive mass located around the pancreas and right hepatic lobe. In the transoperative macroscopic observation, multiple white nodules were visualized in the liver, pancreas, mesentery, intestine, stomach and peritoneal wall. Immunohistochemical examination revealed that neoplastic cells demonstrated a strong positivity for AE1/AE3 and CK20. A sparse immunoreactivity to chromogranin A was observed, which demonstrates neuroendocrine cell labeling. The histopathologic changes associated with the immunohistochemical profile confirmed the diagnosis of metastatic carcinoma with neuroendocrine differentiation, originating from the pancreas. Relevance and novel information: Neuroendocrine tumors of the pancreas are rare and are associated with a poor prognosis in humans. In humans, approximately 7% of neuroendocrine tumors develop in the pancreas, and the 5-year survival rate for a pancreatic neuroendocrine tumor is 53%, according to the American Cancer Society. To our knowledge, only one case has been described in the feline species so far. Due to the rarity of this type of tumor in cats, there is little information about predisposition related to age, sex or breed, as well as the main clinical signs presented, survival time and treatment options.