Adult extracardiac rhabdomyoma (ER) is a rare, slowly growing, benign tumor of skeletal-muscle origin that has a strong predilection for the head and neck. Complete surgical resection has been proposed as the treatment of choice. We describe a case of adult ER that manifested as a nasopharyngeal mass. The diagnosis was made by transnasal endoscopic biopsy, and the patient was managed conservatively. We discuss the current knowledge regarding the clinical presentation, diagnosis, and treatment of adult ER of the parapharyngeal space, and we propose a new concept for treating this tumor nonsurgically in appropriately selected patients.