RESUMEN
Sclerosing encapsulating peritonitis (SEP) is a rare condition which consists of reactive fibrous tissue proliferation with mixed inflammatory infiltration within the abdominal cavity. The present report describes an additional case of SEP affecting a mixed-breed immature female dog presented with persistent vomiting, progressive weight loss, and ascites. Abdominal radiographic and ultrasonographic findings suggested abdominal neoformation resulting in gastric displacement, in addition ascitic fluid was evaluated and cytology showed large numbers of inflammatory effusion. An exploratory laparotomy was performed and were detected multiple thick peritoneal adhesions which restricted mobility of abdominal viscera. Biopsy specimens of these lesions were submitted for histopathological examination. Microscopically, the external serous surfaces of the abdominal organs were covered with dense fibrous connective tissue characterized by intense mature collagen deposition and moderate angiogenesis. The animal was euthanized due to poor prognosis and sent for necropsy. The clinical, imaging, gross and microscopic findings were compatible with SEP.(AU)