The onion peel sign (also called the Cumbo sign or double arch sign) is a feature seen with complicated pulmonary hydatid cyst in which the gas lining between the endocyst and pericyst has the appearance of an onion peel. It is pathognomonic for a ruptured hydatid cyst.
History and etymology
It was first described by Cumbo in 1921 2.
- 1. Polat P, Kantarci M, Alper F et-al. Hydatid disease from head to toe. Radiographics. 2003;23 (2): 475-94. Radiographics (full text) - doi:10.1148/rg.232025704 - Pubmed citation
- 2. Benson CD, Evans WA, Zuelzer WW. Echinococcus cyst of lung exhibiting unusual radiologic and surgical features. Annals of surgery. 117 (2): 268-77. Pubmed