Objective: The purpose of this series was to describe the prenatal diagnosis and pregnancy outcome of fetuses affected by a transient idiopathic fetal sternal cyst.
Methods: Two fetuses had the diagnosis of an isolated presternal cyst at routine sonography at 15 weeks. A follow-up sonographic examination was done, and the neonates were examined after birth.
Results: In both cases, the cyst disappeared at 20 weeks' gestation, and both fetuses had only a small dimple at the location of the cyst.
Conclusions: An isolated presternal cyst is an extremely rare finding. It should be followed sonographically, and if it disappears within a few weeks, the diagnosis of a dermal inclusion cyst should be suspected. Parents can be informed to anticipate a small depression on the neonate's chest.