A 36-year-old woman comes to the office due to firm, nontender swelling of her right cheek for the past 4 months. The patient has had no fever, runny nose, sore throat, or cough. She drinks a glass of wine with dinner on most nights but does not use tobacco. Physical examination shows fullness of the preauricular space on the right side. An MRI of the region identifies a 2.2-cm mass in the right parotid gland, and a follow-up core needle biopsy shows the lesion to be neoplastic. If left untreated, this patient is most likely to develop which of the following?

Question

A 36-year-old woman comes to the office due to firm, nontender swelling of her right cheek for the past 4 months.  The patient has had no fever, runny nose, sore throat, or cough.  She drinks a glass of wine with dinner on most nights but does not use tobacco.  Physical examination shows fullness of the preauricular space on the right side.  An MRI of the region identifies a 2.2-cm mass in the right parotid gland, and a follow-up core needle biopsy shows the lesion to be neoplastic.  If left untreated, this patient is most likely to develop which of the following?

Quizplus · Accepted Answer

11ec160b_35aa_7eaf_9249_2f70d2672127_MD0001_00 The extracranial portion of the facial nerve (CN VII) carries motor innervation to the muscles of facial expression. This nerve exits the skull through the stylomastoid foramen and courses within the substance of the parotid gland. Within this gland, the facial nerve divides into its 5 terminal branches (temporal, zygomatic, buccal, mandibular, and cervical). Parotid gland tumors can compress and disrupt the ipsilateral facial nerve and its branches, causing facial droop. In fact, most parotid gland tumors causing facial nerve paralysis are malignant neoplasms. (Choice A) Bitemporal hemianopsia typically results from tumors (eg, craniopharyngioma, pituitary adenoma) within the sella turcica that compress the optic chiasm. (Choice C) The trigeminal nerve (via its 3 branches) provides sensation to the face and motor innervation to the muscles of mastication. This nerve follows a deep course and is unlikely to be damaged by a tumor of the parotid gland. (Choice D) The recurrent laryngeal nerve is a branch of the vagus nerve that loops below the aortic arch on the left and below the subclavian artery on the right to provide motor innervation to the laryngeal muscles. During thyroid surgery, this nerve may be damaged due to its proximity to the inferior thyroid artery. Unilateral nerve injury often causes hoarseness, whereas bilateral injury may cause inspiratory stridor and respiratory distress due to complete vocal cord paralysis. (Choice E) Horner syndrome presents with partial ptosis, miosis, and anhidrosis due to interruption of the sympathetic innervation to the head. This can occur with lesions affecting the lateral hypothalamus, hypothalamospinal tract, paravertebral sympathetic chain/stellate ganglion (eg, Pancoast tumor), or internal carotid artery (eg, carotid dissection). (Choice F) Strabismus (improper alignment of the eyes) can result from disorders of the extraocular muscles or the nerves that innervate them (CN III, IV, or VI). Educational objective: The facial nerve (CN VII) exits the stylomastoid foramen and courses through the substance of the parotid gland, where it divides into its 5 terminal branches that innervate the muscles of facial expression. Malignant tumors of the parotid gland often compress and disrupt the facial nerve and its branches, causing ipsilateral facial droop. __________ References: The presence of facial nerve weakness on diagnosis of a parotid gland malignant process. (http://www.ncbi.nlm.nih.gov/pubmed/22179671) Parotid gland tumors and the facial nerve. (http://www.ncbi.nlm.nih.gov/pubmed/27040587)

A 36-Year-Old Woman Comes to the Office Due to Firm