I am looking for any information on parotid tumors. My 64-year-old mother was diagnosed with one. She goes to have an MRI next week. I am interested in the possibility of it being malignant and the risks involved in removing it. If it is malignant, what treatments are performed?

Q.

The parotid glands are a pair of salivary glands that lie at the sides of the face, just below and in front of the ears. Only 20 percent of parotid tumors are malignant, so the odds are in your mother's favor. Going one step beyond the benign/malignant distinction, there are many different types of parotid tumors, and there are some subtle (and some not-so-subtle) treatment differences depending upon the specific tumor type.

MRI can help the doctor distinguish amongst the various tumor types, but the best tool for diagnosis is a "fine-needle aspiration biopsy" (FNAB). The doctor will insert a slender needle into the lump, and will then aspirate (suck out) a sample of cells from within the lump. A pathologist will examine the cells under a microscope to determine the specific tumor type.

Whether the tumor is benign or malignant, treatment usually requires surgical removal of the portion of the gland containing the tumor. The parotid gland is composed of a "deep lobe" and a "superficial lobe." The two lobes are separated by the facial nerve, the nerve that allows you to smile, frown, close your eyes, wrinkle your brow and so forth. The main trunk of the facial nerve emerges from the base of the skull behind and below the ear. As it travels into the face, it divides into many branches. Each individual branch travels to a target muscle (in the neck, around the lips, around the eyes ... you get the idea).

The MRI may demonstrate whether the tumor is in the deep or superficial lobe. If the facial nerve is underneath the tumor, the operation to remove the tumor is called a "superficial parotidectomy." If the tumor is underneath the nerve, the operation is called a "total parotidectomy."

The most worrisome risk of parotidectomy is injury to the facial nerve. A small degree of weakness is not uncommon after this operation. Severe injury of the nerve leading to complete or partial facial paralysis is, fortunately, an uncommon complication. Total parotidectomy places the nerve at more risk than does superficial parotidectomy. Other risks of parotidectomy include pain, bleeding, infection and recurrence of the tumor. Numbness of the ear and of the skin surrounding the incision are very common.

If the tumor is malignant, parotidectomy may be the only treatment necessary. Some malignant tumors require further treatment, however. Tumors that commonly spread (metastasize) to lymph nodes in the neck may require a "neck dissection" in order to completely eradicate the tumor. In this operation, lymph node-bearing tissues are dissected from the patient's neck on the same side as the tumor.

Some malignant tumors are very aggressive, and a combination of surgery and radiation therapy is required to achieve the best chance for cure. Chemotherapy is reserved for parotid lymphomas and malignant parotid tumors that have spread to distant areas of the body.