Branchial cyst side predilection: fact or fiction?

Objectives: It is a common teaching that two thirds of branchial cysts occur on the left side of the neck. We reviewed the evidence behind this statement and assessed whether they actually do present twice as often on the left side. Methods: Our study comprised two parts: 1) a historical review of branchial cysts and 2) a retrospective review of 91 histologically confirmed cases operated on at two British hospitals in the years 1999 to 2005. The side of the branchial cyst was recorded. Results: Early studies on branchial cysts did not always rely upon histologic diagnosis; the definition of a branchial cyst has varied throughout medical history. The statement "two thirds of branchial cysts occur on the left" is based upon these early studies in which the definition was variable. In our study, right-sided branchial cysts were actually more common than left-sided branchial cysts (53.8% versus 45%; Χ 2 test, p =.399). One percent were bilateral. Conclusions: Ours is the largest single study in the past 50 years to look at the side predilection of branchial cysts in terms of histologic proof. We propose that branchial cysts may not present more commonly on the left side of the neck, as is commonly taught in medical schools.