The Parotid gland is the salivary gland which is situated laterally near the mandible.
Approximately 75% of neoplasms of salivary glands occur in the parotid glands.
80% of Parotid tumors are benign and of these 80% are Pleomorphic adenomas.
➣ Any age, no gender predilection.
➣ 75% of all parotid tumors.
➣ Over 60 years of age.
b) Warthin’s tumor:
➣ Over 60 years.
➣ Male to female ratio is 4:1.
➣ Consists 15% of all parotid tumors.
a) Acinic cell Carcinoma: Low grade malignancy.
b) Adenoid Cystic carcinoma: Commonly seen in USA. Invariably fatal due to perineural spread and pulmonary metastasis.
c) Adenocarcinoma and Squamous Cell Carcinoma: Both have poor prognosis. Very rare. ( 25% have 5-year survival)
Mostly infants affected. Frequent spontaneous regression of any gland affected in this group.
- All parotid neoplasms are radioresistant.
- No formal biopsy should be performed in parotid tumors except in tumors of ectopic salivary gland e.g. palatal salivary gland.
Criteria of malignant change in mixed parotid tumor:
- Sudden and rapid increase in size.
- Painless tumor becomes painful and tender.
- Feels stony hard.
- Growth becomes fixed to the deeper structures e.g. masseter, mandible.
- Overlying skin may become fixed to the swelling and looks and feels reddish blue and hot.
- Evidence of facial nerve involvement causing asymmetry of face and difficulty in closing the eye.
- Areas of anesthesia over the skin.
- Jaw movements become restrained.
- Veins over the swelling become prominent.
- Enlargement of cervical lymph node.
- There may be evidence of disseminated blood borne metastasis.
- Benign: Superficial parotidectomy.
- Malignant: Radical parotidectomy or total conservative parotidectomy.
- Malignant metastatic lymph nodes may be treated by radical neck dissection or by radiotherapy.
Differential diagnosis of parotid swellings:
- Winged mandible.
- Masseteric hypertrophy.
- External carotid aneurysm.
- Pre- Auricular lymph node.