Infected Thornwaldt Cyst: Case Report of an Unusual Cause of Pediatric Neck Pain.

BACKGROUND: The differential diagnosis for pediatric neck pain is broad and includes benign and life-threatening entities. The neck is a complex structure with many compartments. Rare disease processes exist that can mimic more serious conditions, such as meningitis. CASE REPORT: We present a case of a teenager with several days of severe pain underneath her left jaw, limiting the motion of her neck. After laboratory and imaging evaluation, the patient was found to have an infected Thornwaldt cyst and was subsequently admitted for IV antibiotic treatment. WHY SHOULD AN EMERGENCY PHYSICIAN BE AWARE OF THIS?: Including infected congenital cysts on the differential for pediatric neck pain can help ensure appropriate use of invasive procedures, such as lumbar puncture. Missed cases of infected congenital cysts could lead to patients returning to the emergency department with persistent or worsened symptoms.