PAROTID TUMORS Among the salivary glands that we have, the parotid glands are the largest. There are two parotid glands one on each side. Located in front of the ears, these glands extend down to the upper part of the neck. The glands secrete saliva that is carried through a duct that opens on the inner surface of the cheek adjacent to the second upper molar. Just like in any other part of the body, the parotid glands may develop abnormal growths or tumours. A wide variety of tumours may occur within the parotid glans but the majority, more than 80%, are benign.  Among the benign tumours, the commonest is PLEOMORPHIC ADENOMA.  Some of the benign tumours like the pleomorphic adenomas can be potentially malignant. Malignant tumours of the parotid gland are of several types and their behaviour may vary from being low grade, moderate or high grade malignancy. The parotid gland also contains tissue that is non-parotid in origin. This includes lymph nodes, nerves and vessels. Growth involving these structures may also masquerade a parotid tumour.

Presentation: Patients with a parotid tumour typically present with a swelling around or just below the ear lobule.  This swelling may be vary in size and consistency.

Diagnosis: The diagnosis is established from a detailed history, examination and a high index of suspicion. When a parotid tumour is suspected some investigations are done to confirm the diagnosis.

These include imaging studies such as CT or MRI scan and a fine needle aspiration. Imaging studies provide information regarding the size and extent of the tumour which is useful in planning the surgery. Fine needle aspiration involves aspirating some cells from the tumour which in some cases may provide information of the cell-type of the tumour. As there are many types of tumours that can originate in the parotid gland a pre-operative diagnosis is of the cell-type is very useful in planning surgery.

Pleomorphic Adenoma:  Pleomorphic adenoma is the commonest tumour of the parotid gland. ( Pleo = many, morphic = forms, adenoma = benign tumour) Literally pleomorphic adenoma means a “benign tumour that may have several forms”.  Though the tumour is benign and slow growing, it is potentially malignant and needs to be completely removed. It also has a tendency to recur unless it is completely removed with a wide margin.

 

Treatment: The standard treatment for parotid tumours is surgery which involves removal of part or whole of the parotid gland. In some situations, where the fine needle aspiration had not been diagnostic removal of the tumour also provides a histological diagnosis. A complete removal of the tumour is sufficient for most benign parotid tumours. Malignant parotid tumours may require additional treatment such as radiotherapy/chemotherapy.

 

Parotid_tumor_MR_01

white arrows pointing to a large tumour in the left patotid gland. Fine needle aspiration was suggestive of PLEOMORPHIC ADENOMA

Parotid_tumor_MR_02

Contrast enhanced MRI scan: Black arrow pointing to the parotid tumour. The tumour “lights up” with contrast .