Abstract | November 8, 2021
Meconium Pseudocyst in a Preterm Infant: A Rare Surgical Condition
Learning Objectives
- Meconium pseudocyst formation is rare in meconium peritonitis. It should be considered as a differential diagnosis when an echogenic intra-abdominal cyst is seen.
- Prenatal appearance can be complemented by signs of bowel obstruction, like, polyhydramnios and fetal bowel dilation.
- More than 85% of cases of pseudocyst can be diagnosed as calcified cyst on X-ray. However, histopathology and per-operative findings help to differentiate the cystic form of meconium peritonitis from a pseudocyst. The pseudocyst consists of dilated thinned out intestine filled with meconium that has smooth muscle layer connecting the cyst to the normal intestine. In contrast, cystic-type meconium peritonitis has a fibrous wall.
Introduction: Meconium peritonitis is caused by antenatal bowel perforation with spillage of meconium into the peritoneum resulting in sterile peritonitis and formation of dystrophic calcifications. When the extruded meconium becomes walled off, it can form a rim-calcified mass representing meconium pseudocyst. Histopathological confirmation is fundamental, by showing smooth muscle in the cystic wall.
Case Presentation: A 23-year-old primi mother was admitted at 27 weeks of gestation with a complaint of leaking per vagina. Antenatal scans at 24 and 26 weeks of gestation revealed abnormal findings of polyhydramnios and fetal ascites. The mother did not receive antenatal steroids and underwent a cesarean section for the pre-labor rupture of membranes. Bag and mask ventilation was initiated and the baby was intubated and mechanically ventilated due to poor respiratory effort. On physical examination, the baby had generalized abdominal distension with abdominal wall erythema. The patient received a dose of surfactant and was transferred to the NICU. Urgent X-ray abdomen showed areas of calcification. Abdominal ultrasound showed a cyst with coarse areas of calcification in the right iliac fossa. On day 2 of life baby had hematochezia with worsening abdominal distension. X-ray abdomen on day 5 of life showed a large calcified cyst in the central abdomen.
Final Diagnosis: Meconium pseudocyst.
Management/Outcome: Pediatric surgery was consulted. Exploratory laparotomy was performed and the infant was found to have a large meconium pseudocyst in the central abdomen with collapsed proximal and distal bowel loops. A copious amount of meconium was removed, pseudocyst was resected, and ileostomy was performed. Histopathological examination of resected cyst confirmed meconium calcified cyst. Mutation analysis was negative for cystic fibrosis. The patient was extubated on postoperative day five. Tube feeds were started with an initial course complicated by feeding intolerance. As the patient tolerated feeds, she was discharged at 35 weeks postmenstrual age.
