Abstract
INTRODUCTION: Foregut duplication cysts are rare mediastinal malformations that can cause life-threatening respiratory compromise in early infancy and are often misdiagnosed on initial imaging. PRESENTATION OF CASE: A three-month-old boy, born at 37 weeks, developed progressive respiratory distress and cyanosis unresponsive to pneumonia therapy. Chest radiography suggested a hiatal hernia, whereas thoracic ultrasound showed a multiloculated cyst. Contrast-enhanced CT delineated a thick-walled paracardial cyst crossing the diaphragm and a smaller posterior chest-wall cyst. On hospital day 8 a right thoraco-abdominal approach allowed en-bloc removal of the 6 × 4 cm lesion with mucosectomy of the adherent esophageal segment and excision of the posterior cyst. Histology confirmed gastric-type foregut duplication. The infant was extubated on postoperative day 1, reached full feeds by day 7, and was discharged asymptomatic on day 18. DISCUSSION: This case illustrates the diagnostic pitfalls of mediastinal foregut duplication cysts masquerading as more common entities such as hiatal hernia. Multimodal imaging-particularly ultrasound and CT-was pivotal in defining lesion extent and guiding timely surgery. Complete thoraco-abdominal excision achieved rapid recovery and mitigated risks of infection, hemorrhage, or malignant transformation reported with incomplete resection. CONCLUSION: Neonates with unexplained respiratory distress and mediastinal masses should prompt consideration of foregut duplication cysts. Early cross-sectional imaging and definitive surgical excision are essential for preventing complications and ensuring excellent long-term outcomes.