Abstract
Background: Teratomas are germ cell tumors derived from three embryonic germ layers. Most of them are benign mature teratomas and are frequently observed in the sacrococcygeal region, gonads, and mediastinum, the occurrence of immature teratomas in the gastric wall is extremely rare.
Case summary: A 31-year-old pregnant woman's ultrasound at 36 weeks revealed a mass in the fetus's left mid-abdominal cavity. An immature teratoma originating from the stomach wall was suggested by neonatal CT and ultrasound scans. The neonate successfully underwent tumor excision, with pathology affirming the diagnosis.
Conclusions: Immature gastric teratomas are rare tumors with malignant potential. Their diagnosis leans heavily on ultrasonographic features and histopathology. The case highlights the diagnostic utility of prenatal ultrasound. Currently, total resection of the tumor is the recommended treatment.