A single-center experience of magnetic resonance imaging findings of fetal sacrococcygeal teratomas.

Background: Sacrococcygeal teratomas (SCT) are known as rare tumors, but they are the most common tumor in fetuses and newborns. This study aims to present fetal magnetic resonance imaging (MRI) findings of SCT diagnosed prenatally and compare them with that of the prenatal Ultrasound (US) findings.

Methods: Eleven patients diagnosed as SCT prenatally by US and further assessed by MRI are included. MRI was performed via a 1.5-T magnet with a body coil. The presence, size, content extension, and compressive effects of each mass were determined and correlated with US findings and with postnatal examinations, including surgery and pathology. As complications, the presence of ascites and skin edema or pleural or pericardial effusion was diagnosed as hydrops. The amniotic fluid index was calculated for the assessment of oligo- or polyhydramnios.

Results: US findings are found strongly correlated with MRI findings. An agreement on the extent of each mass was observed in eight patients, disagreement in one fetus was an extension of the tumor within the spinal canal recognized only at MR and assessment of intrapelvic-abdominal extension was superior in MRI. There were n = 6 type I, n = 2 type II, n = 1 type III and, n = 2 type IV tumors. MRI was superior to US for detecting displacement of the colon (n = 3), intrapelvic-intraabdominal extension (n = 1), urinary tract complication (n = 2), and intraspinal extension (n = 1).

Discussion: MRI is found to be superior to US especially in the assessment of intrapelvic and intraspinal extension of the tumor, colonic displacement, and complications.