Purpose or Case Report: Teratomas uncommonly manifest in the gastrointestinal system, and most international literature cites the total number of gastric teratomas reported to be approximately 120. Of these, only 12-30 are of the immature variety. Reports of immature gastric teratoma in the United States are scant. Presented here are images from what appears to be the first known fetal MRI to demonstrate a gastric immature teratoma with follow-up radiographic, fluoroscopic, and CT imaging of the infant.
Methods & Materials: A 24-year-old G 5 P 2 gravid female presented for fetal MRI following an abnormal antenatal ultrasound which showed a complex abdominal mass. The MRI was obtained 34 weeks, 5 days. The child was later born at term, and serial radiographs were acquired followed by a CT of the abdomen and pelvis on the 4th day of life. Upper GI was performed on the 6th day of life.
Results: Fetal MRI revealed a lobulated, predominantly cystic mass occupying nearly the entire left hemiabdomen with internal septations and T2 hypointense nodules. The mass appeared to circumscribe the stomach. A normal distribution of meconium was present throughout the bowel. The patient was counselled by the radiologist at the time of the MRI who informed the patient that the most likely etiology for the mass was a meconium pseudocyst. Following delivery, an abdominal radiograph supported this diagnosis, as a large upper abdominal mass containing scattered internal calcifications was observed displacing multiple gas-filled bowel loops. The subsequent CT showed these central calcified components within both lobes of a bilobed upper abdominal mass. The left lobe of the mass was predominantly fluid attenuation, and the right lobe exhibited thickening and enhancement of the septations. Contrast flowed freely into the stomach and circumscribed the right lobe of the mass during an upper GI. The left lobe of the mass was not intraluminal. Contrast emptied into the duodenum and small bowel without evidence of obstruction. The mass was shown to represent an immature gastric teratoma following surgical resection.
Conclusions: Immature gastric teratoma is an exceedingly rare diagosis. Several imaging features suggested the much more common entity of meconium pseudocyst, and even CT failed to show macroscopic fat within the lesion. This case highlights the value of a multimodality approach to a case of an unusual pathology.