EP12.05: Ultrasound appearance of fetal giant thymus

Abstract

Obstetrical ultrasound screening offer the possibility to assess the fetal thymus, which is located in the immediate proximity of the sternum, in the anterior superior mediastinum; the abnormal values of its measurements are high suggestive for a genetic disorder rather than a reflection of a pathological function of fetal immune system. Although there are several studies that report the existence of a significant correlation between fetal thymus involution and Trisomy 21, DiGeorge syndrome, intrauterine growth restriction, acute fetal distress, malnutrition or trauma, chorioamnionitis, also neonatal sepsis and acute respiratory distress syndrome, eventual correlation between an abnormal large fetal thymus and associate adverse pregnancy outcome has not been demonstrated. We present three cases of abnormal size of a fetal thymus lobe, detected by routine obstetrical ultrasonography after 30 weeks of gestation. The thymus had the ultrasound appearance of a hypo echoic avascular paracardiac supradiaphragmatic mass, movable synchronously with heart pulsations, with clear delimitation by the ventricular wall and the surrounding pulmonary tissue, measuring about 30/20 millimetres. All three pregnancies resulted in perfect health newborns, with normal involution of the thymus during the first six months of life and fitting in the normal range for age during childhood. We report this cases in order to emphasise the possibility of an abnormal large physiological development of the thymus, in the context of differential diagnosis with fetal cardiac tumours, thymic cysts, thyroid masses, teratomas, vascular anomalies and other pulmonary or mediastinal masses.Supporting information can be found in the online version of this abstract We report on a 39-year-old IIG IP, whose male fetus was sonographically diagnosed in the 25 week of the pregnancy with a smoothly limited 17x15x21 mm cyst in Douglas. Urinary bladder and intestine were well separated from the cystic findings. There were no abnormalities in the kidneys and the urinary tract. A connection to the spinal canal was not shown. The previous extended ultrasound diagnosis in the first and second trimesters revealed no abnormalities. By the time of birth, the findings in Douglas were slightly increased in size. The postpartum pediatric radiological ultrasound diagnostics showed that the cyst originated from the right sperm bladder. The observation has shown a complete spontaneous reconstruction of the cystic findings. Cysts of the seminal vesicle are more common in the childhood. In the prenatal phase, however, such cyst is a rarity.Supporting information can be found in the online version of this abstract A 38-year old woman, pregnancy 2, parity 1 was scanned at the first trimester in our hospital. Her obstetric history showed a delivery at term with low molecular weight heparin, because a previous thrombosis in her upper limb. The scan in the 12 weeks showed a reverse wave in ductus venosus, with normal uterine arteries, and a low risk for aneuploidy. During the 17 wee...