title: Image diagnosis: arachnoid cyst.
abstract: A 14-year-old boy presented with 3 months of generalized headache that had increased in intensity and frequency with associated light-headedness. Primary arachnoid cysts result from developmental abnormalities; more rare secondary cysts develop as a result of head injury, meningitis, tumors, or as a complication of brain surgery.
authors.affiliation: Premedical Student and a Scribe in the Emergency Department at Mission Hospital Regional Medical Center in Mission Viejo, CA. akarnaze2123@gmail.com.
authors.forename: Andrew C
authors.initials: AC
authors.lastname: Karnazes
authors.affiliation: Emergency Physician at the San Diego Medical Center in CA. jonathankei@kaiser-ed.com.
authors.forename: Jonathan
authors.initials: J
authors.lastname: Kei
authors.affiliation: Emergency Physician at Mission Hospital Regional Medical Center in Mission Viejo, CA. mvanle@gmail.com.
authors.forename: Minh V
authors.initials: MV
authors.lastname: Le
mesh_terms: D000293:Adolescent; D016080:Arachnoid Cysts / Q000000981:diagnostic imaging*; D006801:Humans; D008297:Male; D014057:Tomography, X-Ray Computed