[Encapsulating peritonitis in periodic disease. Apropos of a case studied by x-ray computed tomography].

A case of encapsulating peritonitis complicating the course of familial Mediterranean fever is reported. This encapsulating peritonitis was responsible for abdominal pain and had a "pseudocystic" appearance on ultrasonography and computed tomography. Ultrasound guided aspiration produced a yellowish fluid rich in proteins and poor in cells. Surgical operation revealed a congested appearance of the peritoneum associated with a richly fibrinous appearance of the external wall of the mass. The differential diagnosis is discussed.