The lying down adrenal 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 1, straight 2, elongated 2, or pancake adrenal gland 3,4.
It can be a useful sign to confirm renal agenesis when the kidney is not visualized during antenatal ultrasound 5,6, as well as during postnatal imaging of patients to distinguish from postnephrectomy state.
- 1. Sargar KM, Khanna G, Hulett Bowling R. Imaging of Nonmalignant Adrenal Lesions in Children. (2017) Radiographics : a review publication of the Radiological Society of North America, Inc. 37 (6): 1648-1664. doi:10.1148/rg.2017170043 - Pubmed
- 2. Kawashima A, Sandler CM, Fishman EK, Charnsangavej C, Yasumori K, Honda H, Ernst RD, Takahashi N, Raval BK, Masuda K, Goldman SM. Spectrum of CT findings in nonmalignant disease of the adrenal gland. (1998) Radiographics : a review publication of the Radiological Society of North America, Inc. 18 (2): 393-412. doi:10.1148/radiographics.18.2.9536486 - Pubmed
- 3. Virginia B. Planz, Raymond B. Dyer. The “pancake” adrenal. (2015) Abdominal Imaging. 40 (6): 2041. doi:10.1007/s00261-014-0287-6 - Pubmed
- 4. Dyer RB, Chen MY, Zagoria RJ. Classic signs in uroradiology. Radiographics. 2004;24 Suppl 1 (suppl 1): S247-80. Radiographics (full text) - doi:10.1148/rg.24si045509 - Pubmed citation
- 5. Hoffman CK, Filly RA, Callen PW. The "lying down" adrenal sign: a sonographic indicator of renal agenesis or ectopia in fetuses and neonates. J Ultrasound Med. 1992;11 (10): 533-6. J Ultrasound Med (abstract) - Pubmed citation
- 6. Majmudar A, Cohen HL. "Lying-Down" Adrenal Sign: There Are Exceptions to the Rule Among Fetuses and Neonates. (2017) Journal of ultrasound in medicine : official journal of the American Institute of Ultrasound in Medicine. 36 (12): 2599-2603. doi:10.1002/jum.14315 - Pubmed