The parotid glands are located in front and beneath the ear. Facial nerve is transvers through parotid gland. The main function of facial nerve is motor control of all of the muscles of facial expression.
Mostly patient have a painless, mass in front and beneath ear. Pain is more frequently associated with malignant disease. Pain may associate with involvement of deeper structure or involvement of facial nerve.
Fine needle aspiration cytology (FNAC) is the primary diagnostic tool. Open biopsy should be avoided in parotid gland tumour due to risk of facial nerve involvement.
Parotid gland cancers are diverse with respect to origin and pathology. The most common histopathologic types are mucoepidermoid carcinoma, adenoid cystic carcinoma, adenocarcinoma, etc.
Parotid surgery with negative margin is main treatment. Adjuvant treatment in the form of radiotherapy, depending upon histopathology report.
Parotid gland consists of two lobes, the superficial lobe and deep lobe. The two lobes are separated surgically by facial nerve. The facial nerve controls facial expression like ability to close eyes, raise eyebrows, smile etc.
Most commonly performed parotid surgery is superficial parotidectomy for benign or low grade small parotid cancer. Now adequate parotidectomy with negative margins is also an option for benign tumors. Facial nerve preserving total parotidectomy is required for high grade and larger parotid cancer. Prophylactic Neck dissection may be indicated for high grade and larger tumors. Therapeutic neck dissection is required for N+ neck disease.
In total parotidectomy, special care is taken to preserve facial nerve. In case of facial nerve involvement, involved segment is resected along with the tumor and nerve grafting is done.
Postoperative complications include temporary facial nerve branches dysfunction in around 25-40% cases as described in literature and generally recovers in 8-12 weeks. Permanent facial nerve injury can happen in 1-2% of cases depending upon location and extent of parotid cancer.
Post op radiotherapy indicated in advanced stage, high grade and recurrent disease. Role of adjuvant chemotherapy is still investigational.
