pancake sign , oreo sign , lying down adrenal sign in fetal ultrasound

The lying down adrenal , pancake sign or oreo sign sign is a cross-sectional imaging sign of renal agenesis or ectopia in which the ipsilateral adrenal gland appears to be ‘lying down’ on the psoas muscle posteriorly. Due to the linear as opposed to Y-shaped configuration of the gland in such situations, it is also described as the discoid , straight , elongated or pancake adrenal gland It can be a useful sign to confirm renal agenesis when the kidney is not visualized during antenatal ultrasound