P2.L232: Kidneys on the loose: three cases of pediatric intrathoracic kidney and co-existing Bochdalek hernia

Introduction: Renal ectopia is a rare condition where the kidney is abnormally positioned. Among all renal ectopias, intrathoracic kidney (ITK) is the least frequent. Here, we present 3 atypical cases of congenital diaphragmatic hernia (CDH) with ITK treated in a level IV NICU, and we compare them with those in literature.

Case Description: Case 1: Male born at 38 weeks with a prenatal diagnosis via fetal MRI of CDH and ITK. Surgery performed successfully at bedside on day 3 of life. Incidentally, patient developed euthyroid sick syndrome.
Case 2: Male born at 38.2 weeks. At birth, patient presented with acute respiratory distress. Initial X-ray demonstrated left CDH containing the left kidney, bowel loops, and part of the spleen. He was intubated and placed on mechanical ventilation. Laparotomy performed on third day of life. Hospital stay complicated with cholestasis.
Case 3: Male born at 39.5 weeks, who was transferred after he was postnatally diagnosed with CDH and ITK. Surgical repair at bedside on day 3 of life. Hospital course complicated by duodenal malrotation.

Discussion: Most ectopic kidneys are found in the pelvic and lumbar regions secondary to failure to ascend during fetal life. ITK is the rarest form of ectopic kidney but when it is present it is generally associated with CDH, like in this case series. Only 12 cases of renal herniation associated with CDH have been described in literature, with the majority being right-sided and affecting females. Interestingly, all of our cases were male and left-sided. In contrast to diaphragmatic hernia with liver herniation, infants with ITK generally do better. No anatomic variant or abnormality associated with the kidneys have been seen or reported on prenatal MRI or intraoperatively in any of the cases described. Notwithstanding a significant proportion of CDH, up to 50%, may be associated with structural or chromosomal anomalies. This emphasizes the importance of conducting a comprehensive evaluation and seeking genetic consultation in all cases. Even though the karyotype and chromosome microarray were normal in our 3 cases, we cannot definitively rule out any underlying association of ITK and CDH since data is insufficient and genetic testing was not always mentioned on prior reports. Infants with CDH often face long-term complications such as respiratory issues, nutritional problems, neurodevelopmental delays, among others. Nevertheless, there is a lack of long-term follow-up data for children with CDH and ITK. Further evaluation is recommended to monitor future potential renal complications.

Conclusion: We highlight the key aspects of ITK associated with CDH. Due to its variability and complexity, much remains to be discovered. Further research and long-term follow-up are crucial to better understand and address the challenges of this condition.