The first bite syndrome occurs due to a damage of sympathetic innervation to the parotid gland that results in denervation supersensitivity of myoepithetlial cell sympathetic receptors. A supramaximal response by the myoepithelial cells is elicited on cross-stimulation by the release of parasympathetic neurotransmitters induced by chewing. It presents as pain in the parotid region after the first bite of each meal that improves with each subsequent bite. Most cases occur as a postoperative complication of parapharyngeal space surgery. However, there are reports of this syndrome as a first symptom of tumours not yet operated. We report a case of a patient with first bite syndrome after resection of a voluminous pleomorphic adenoma in the parapharyngeal space. A female patient aged 36 presented with a mass located in the parapharyngeal space, incidentally identified in a sella turcica MRI. The patient was completely asymptomatic and the physical exam non-informative. The parapharyngeal mass was approached by a transcervical incision. During the surgery, the external carotid artery was transiently clamped. The syndrome appeared during the first postoperative month and has not changed after 8 months. According to some authors, ligation of the external carotid artery may be enough to injure the sympathetic fibbers to the parotid gland, originating from the external carotid artery. Symptoms range from mild to severe and may significantly affect the patient’s quality of life. The use of botulinum toxin seems the most effective treatment. However, most reported cases show that the syndrome resolves spontaneously with time. It is important to maintain a high level of suspicion for malignancy in patients with this syndrome in the absence of surgery. There are reports of neoplasms in the parapharyngeal and submandibular space whose initial imaging fails to demonstrate a mass and first bite syndrome was the first symptom.
Key words: first bite syndrome; parapharyngeal space