Parotid Gland

Parotid Gland

Information on the Parotid Gland.

The parotid gland is the largest salivary gland and is located in front of the ear and extends down into the top of the neck. It is the most common site for salivary gland tumours and 80% of these are non-cancerous. Most lumps in the parotid do not have any symptoms and will be found by the patient themselves or on a scan for another medical problem. Rarely, they can present with pain or weakness of the face and these symptoms are more worrying. Any lump in the parotid gland requires further investigation to assess its nature and patients should see a specialist who will take a full history, examination and perform the necessary investigations which will usually involve an ultrasound with biopsy and an MRI scan.

Benign Parotid lumps

  • The most common parotid lump is a pleomorphic adenoma which is non-cancerous. Very occasionally, a pleomorphic adenoma can undergo cancerous change and therefore, it is usually recommended that these are removed.
  • The next most common tumour is an adenolymphoma or Warthin’s tumour which is also benign and in 10% of people occurs on both sides. These can be left (as they do not become cancerous) or removed depending on their size and the patient’s preference.

Cancerous tumours

Cancerous tumours are rare and account for only 20% of parotid lumps and there areseveral different types. Any lumps that are found to be cancerous will be managed through a Head & Neck Multidisciplinary Team. Treatment plans will be tailored to the individual patient, their symptoms and tumour subtype. Symptoms that are concerning for a cancer include pain, overlying skin changes, rapid growth and weakness of the facial nerve. Cancerous lumps in the parotid gland can come from other sites although this is rare, except for skin cancers in the head and neck region which can spread to lymph nodes found in the parotid gland. Any lymph node swelling within the parotid gland should be treated as very suspicious.

Investigations to determine diagnosis

It is important that anyone with a parotid lump undergoes an MRI, ultrasound and core (or needle) biopsy. An MRI scan is used to have a look at the lump, assess the size and characteristics as well as its exact location and association with surrounding structures. It will also help assess whether or not there any other lumps on that side of the neck or in the other parotid gland. An ultrasound scan and core biopsy of the lump is performed to get a sample which can be looked at in the pathology lab to ascertain the type of tumour. This is done with local anaesthetic so that it does not hurt. This will provide an accurate diagnosis in around 90 to 95% of patients when combined with the findings on the ultrasound and MRI. If the lump is thought to be suspicious for cancer, a CT scan of the chest will also be performed.

The procedure

If surgery is recommended, this can be done as a day case with the patient discharged home the same day. Occasionally, it may require an overnight stay in hospital and rarely, 2 nights in hospital are needed. The operation is performed under general anaesthetic and depending on the type of lump and its location, this can either be done as an extracapsular lumpectomy or a formal parotid operation:

  • An extracapsular lumpectomy is performed for noncancerous lumps and involves removing only the lump from the gland.
  • A formal parotid operation takes longer and involves identifying the facial nerve (which supplies the muscles of the face) and working above and/or below it to make sure it is not damaged with removal of the lump and part of the parotid gland.

Risks of parotid surgery

  • The main risk of a parotid procedure is the risk of damage to the facial nerve. The facial nerve controls the muscles of facial expression and damage to the nerve can cause weakness of some or all of facial muscles. The risk of this is low and it is usually temporary with about 75% of weakness recovering however there is a very low risk of permanent weakness.
  • A scar which will becomes less pronounced with time. The incision is often hidden in a skin crease so it is not obvious.
  • Numbness to the ear lobe and part of the cheek is common and occurs in at least 50% of patients, it usually improves a little with time but may not go back to normal. However, usually numbness to the ear lobe settles.
  • Like all operations there is a small risk of a wound infection, bleeding, or a collection of liquid called seroma.
  • Other risks include Frey’s syndrome which is redness and sweating of the skin on the cheek over the gland when eating but this is usually mild and resolves after about a year (the risk of this is reduced with a lumpectomy).
  • A salivary fistula is temporary leaking of saliva into the neck and again this usually settles quickly but may need to be drained with a needle if it becomes uncomfortable.
  • There is always a risk that the lump may return after it’s been removed but this is uncommon.
  • Lastly there is a risk of seeing a minor change in facial contouring if a large amount of the parotid gland is removed.

Post-operative information

The patient will probably have a drain (a small plastic tube to collect excess fluid) left in the wound which will be removed after 4-6 hours or the following day; and skin sutures or clips which need to be removed at the GP surgery 3 to 7 days after the procedure (depending on the type used).

Patients are then seen in clinic for a post-operative follow up appointment after around 2 weeks. If any patient has concerns after the operation, they are welcome to contact Rebecca, our Practice Manager, and we will endeavour to answer your query.