Inflammatory peritonitis secondary to rupture of borderline mucinous ovarian tumor

We present the case of a woman with a history of untreated borderline ovarian tumor. She went to the emergency department with abdominal pain and vomiting. In this context, the first diagnostic possibilities to rule out were tumor progression and/or tumor complication. Inflammatory peritonitis secondary to a ruptured ovarian tumor is a complication that has not been widely discussed. It is a surgical emergency. The differential diagnosis should be made with peritoneal carcinomatosis. The main radiological finding that should make us to suspect this entity is the reduction of tumor's size in an untreated ovarian mass.