Joshi, JayateerthaMushtaq, Owais AhmedSayashi Roy,Rao, Suchetha S.2025-11-122025-11-122022https://hdl.handle.net/20.500.14572/3148Jayateertha Joshi Department of Paediatrics, Kasturba Medical College Mangalore, Manipal Academy of Higher Education, Manipal, Karnataka – 576104, India Owais Ahmed Mushtaq Department of Paediatrics, Kasturba Medical College Mangalore, Manipal Academy of Higher Education, Manipal, Karnataka – 576104, India Sayashi Roy Department of Paediatrics, Kasturba Medical College Mangalore, Manipal Academy of Higher Education, Manipal, Karnataka – 576104, India Suchetha S Rao Department of Paediatrics, Kasturba Medical College Mangalore, Manipal Academy of Higher Education, Manipal, Karnataka – 576104, India https://orcid.org/0000-0002-5232-9727Abstract: Retroperitoneal teratoma is a rare occurrence in neonates. They are usually asymptomatic and the only finding may be abdominal distension. We report an unusual case of a large retroperitoneal teratoma in a neonate who presented with abdominal distension. Imaging done showed a cystic lesion with calcifications, internal septations and fat dense areas. It was successfully managed by surgical excision, findings of which were consistent with that of a mature cystic teratoma. Despite being rare, we must consider retroperitoneal teratomas as a differential diagnosis of an abdominal mass in a newborn. Early detection and complete surgical excision may be life-saving.en-USAlpha fetoproteinlaparotomyretroperitoneal massArticle