Complementary findings on 18F-FDG PET/CT and 18F-NaF PET/CT in a patient with Erdheim-Chester disease

Radiol Bras. 2017 Mai/Jun;50(3):199–208 202 congenital anomalies, such as congenital heart disease and gastrointestinal anomalies. The prenatal diagnosis is based on identification of this pattern of malformation in imaging studies. Sirenomelia is considered a primary developmental field defect affecting multiple midline primordia. In the case reported here, MRI allowed us to make the diagnosis of myelomeningocele, which was identified as cystic hygroma on prenatal ultrasound, and bilateral renal agenesis, thereby confirming severe fetal impairment, which allowed the termination of pregnancy to be authorized. However, not all of the associated malformations were identified prior to the stillbirth; the interventricular communication and gastroschisis were identified only during the autopsy. Congenital heart disease has been associated with sirenomelia, and the fetus evaluated here was also exposed to angiotensin-converting enzyme inhibitors, which could also explain the occurrence of the cardiac defect. The combination of interventricular communication and gastroschisis is not very common; in fact, only two cases, both identified by prenatal ultrasound, have been reported. In a recent review, Feldkamp et al. suggested that gastroschisis is a primary malformation. Our case showed the importance of using a combination of different imaging methods for the diagnosis of a rare congenital anomaly. Although ultrasound continues to be the main diagnostic tool for use during pregnancy, MRI has many advantages, mainly in identifying the fetal morphology. In the case presented here, despite the high quality of the images, the associated malformations were identified only through pathological studies. The unusual anomalies identified in this case were defects of blastogenesis. The combination of prenatal imaging and postnatal autopsy is important to defining the spectrum of associated malformations even when the congenital anomaly is part of a primary developmental field defect.