Successful treatment of sclerosing encapsulating peritonitis in a cat using bioresorbable hyaluronate-carboxymethylcellulose membrane after surgical adhesiolysis and long-term prednisolone.

Case summary: An 8-year-old neutered male domestic shorthair indoor cat was presented with an 8-week history of intermittent vomiting, anorexia and weight loss that had been unresponsive to supportive treatment. Abdominal ultrasound revealed plication of the small intestine and fluid accumulation proximal to the lesion, and a linear foreign body was suspected. An exploratory celiotomy showed cocoon-like encapsulation of the entire intestine. Surgical adhesiolysis and full-thickness biopsy were performed, and histopathologic examination revealed mild thickening of the visceral peritoneum with fibrin deposition, as well as mild neutrophil and lymphocyte infiltration. These findings were compatible with sclerosing encapsulating peritonitis (SEP). The cat recovered well postoperatively and was discharged the next day. Prednisolone was administered for 7 weeks to prevent recurrence of SEP. Five months after surgery, the cat was re-presented with anorexia and chronic vomiting. Based on the clinical examination findings, recurrent SEP was suspected. At the second surgery, surgical adhesiolysis was repeated and a bioresorbable hyaluronate-carboxymethylcellulose membrane was used to cover the serosal surface and thus prevent adhesion formation. Histopathologic findings of the peritoneal biopsy specimen confirmed SEP. Long-term prednisolone treatment (1 mg/kg for the first dose and 0.5 mg/kg every 48 h for maintenance) was administered postoperatively. The cat survived for more than 1239 days without recurrence. Relevance and novel information: To our knowledge, this is the first report of SEP in a cat with long-term survival. The use of a bioresorbable hyaluronate-carboxymethylcellulose membrane and long-term prednisolone treatment may have prevented short-term and long-term recurrence, respectively, in this case.