Tapia Syndrome Secondary to Hypoglossal Nerve Schwannoma: A Case Report on a Rare Medical Condition.

Tapia syndrome (TS) is the ipsilateral palsy of the hypoglossal nerve (CN XII) and the recurrent laryngeal branch of the vagus nerve (CN X). It typically presents with tongue deviation toward the affected nerve, dysphagia, and dysphonia due to unilateral paralysis of the intrinsic tongue muscles and vocal cords. Common etiologies include orotracheal intubation or direct trauma, with nontraumatic peripheral causes rarely reported. We present the case of a 77-year-old woman with progressive hoarseness, dysphagia, and right tongue deviation. She reported no history of intubation, recent surgery, or trauma. Physical examination revealed right tongue atrophy, and rigid laryngoscopy showed bowing of the right vocal fold, severely decreased mobility of the right true vocal cord, and moderate phase asymmetry. MRI imaging identified a 3.2 cm x 1.7 cm mass near the hypoglossal canal extending into the right neck, consistent with a schwannoma compressing CN X and CN XII. The patient was treated with stereotactic body radiation therapy (SBRT), which was well-tolerated. On follow-up, 18 months later, her symptoms remained stable with mild improvement in hoarseness and no progression of the schwannoma on imaging. This case illustrates a rare central cause of TS and discusses the benefits of SBRT when surgery poses high risk.