Retention cyst of the pharyngeal mucosal space is an accumulation of trapped mucous in the mucosa or adenoids of the pharynx. It is a benign lesion, often seen on routine imaging of the head and spine. It is typically a simple cyst originating from the pharyngeal mucosa, without invasion of the surrounding structures. It is important not to misinterpret a retention cyst as a malignant tumor. Patients are usually asymptomatic and do not need treatment