Syncope caused by a pleomorphic adenoma: Case report and literature review.

Pleomorphic adenomas are considered the most common salivary gland tumors, although they rarely occur in the parapharyngeal space. To the best of our knowledge, this is the first case report of a parapharyngeal parotid pleomorphic adenoma causing syncope. A 57-year-old man was admitted for left-sided blurred vision, left-sided weakness, dysarthria, lightheadedness, and syncope. Upon his admission, an electrocardiogram showed sinus bradycardia, and computed tomography of the neck with contrast showed a large parapharyngeal mass involving the prestyloid compartment, leading to compression of blood flow through the internal carotid artery. The mass was biopsied via intraoral fine-needle aspiration, which revealed cytology consistent with pleomorphic adenoma. The mass was resected via a transcervical approach, and a total parotidectomy was performed. The patient's hypotensive and bradycardic episodes disappeared after surgery. Surgical pathology showed a benign pleomorphic adenoma with a hemorrhagic and necrotic center and without capsular invasion or malignant transformation.