Use of tamoxifen in a German shepherd dog with sclerosing encapsulating peritonitis

A German shepherd dog was diagnosed with sclerosing encapsulating peritonitis after an episode of peritonitis caused by a free intra-abdominal foreign body (stick). The foreign body had initially been treated by surgical removal and abdominal lavage. Postoperatively, peritoneal effusion persisted despite the use of methylprednisolone for 1 month and a second surgical exploration and abdominal lavage. After a third surgery at our institution (to breakdown abdominal adhesions) followed by open abdominal drainage, treatment with tamoxifen orally was initiated and within 2 weeks the dog's condition improved dramatically. Two months later, no fluid was present in the abdomen. The only apparent adverse reaction to tamoxifen therapy was swelling of the vulva. In humans, sclerosing encapsulating peritonitis is a known life-threatening complication following peritoneal dialysis. In veterinary medicine, most animals with sclerosing encapsulating peritonitis die because of chronic weight loss, peritoneal effusion and progression of concurrent disease. This dog's condition was unresponsive to methylprednisolone alone but was successfully treated with aggressive surgery including enterolysis and open abdominal lavage and the addition of tamoxifen.