Calcified meconium pseudocyst: X-ray diagnosis of meconium peritonitis at birth.

To cite: Lee GS-yi, Chandran S, Rajadurai VS. BMJ Case Rep Published online: [please include Day Month Year] doi:10.1136/ bcr-2015-211052 DESCRIPTION An infant girl was born at term to a mother diagnosed antenatally to have a fetal abdominal cyst and polyhydramnios. At 32 weeks, fetal imaging showed a calcified lesion (4.5×6.2 cm) in the central abdomen. At birth, a calcified cystic lesion suggesting a meconium pseudocyst (MPC) was noted in the X-ray of the abdomen (figure 1). Abdominal ultrasound scan confirmed a large calcified cyst in the central abdomen. The infant underwent laparotomy due to increasing bilious aspirate. Intraoperatively, they found a large MPC with extensive interloop adhesions and ileal atresia with perforation requiring stoma creation. Histopathological report showed ileal atresia with perforation and a large MPC. The child recovered well and underwent stoma closure at 3 months of age. Fetal meconium peritonitis (MP) is a sterile chemical peritonitis following bowel perforation. Cystic type of MP occurs when the inflamed intestinal loops become fixed, leading to formation of an intraperitoneal cyst with a fibrous wall. When the extruded meconium becomes walled off, it can form a cystic, rim-calcified mass reflecting the normal intra-abdominal healing process to confine the perforation. MPC, a rare presentation of MP, has thinning of the intestinal wall with a smooth muscle layer connecting the cyst to normal intestine and it lacks epithelium due to inflammation. Fetal ultrasonography showing ascites, calcification and bowel dilation strongly indicate MP. In neonates with MPC, X-ray of the abdomen often reveals calcified pseudocyst. X-ray findings in MPC is suggestive but differentiated from cystic type of MP with per-operative findings and histopathology.