[Fetal meconium pseudocyst secondary to in utero perforation of colon transversum and meconium peritonitis].

Fetal bowel intrauterine perforation causes sterile inflammation of the peritoneum, known as meconium peritonitis. In some cases the perforation closes spontaneously, thus forming a meconium pseudocyst between the intestinal loops and the omentum. Meconium peritonitis, complicated by pseudocyst formation, should always be considered when a fetal abdominal mass with diverse echogenicity and hyperechogenic calcifications is observed on prenatal ultrasound. Usually, this is associated with ascites and/or polyhydramnios. The differential diagnosis necessitates exclusion of all other fetal abdominal tumors. We present a case report of meconium pseudocyst diagnosed prenatally at 32 weeks of gestation which was successfully treated by surgery after birth.