Definition

A salivary gland tumor is an uncontrolled growth of
cells that originates in one of the many saliva-producing
glands in the mouth.

Description

The tongue, cheeks, and palate (the hard and soft
areas at the roof of the mouth) contain many glands that
produce saliva. In saliva there are enzymes, or catalysts,
that begin the breakdown (digestion) of food while it is
still in the mouth. The glands are called salivary glands
because of their function.

There are three big pairs of salivary glands in addition
to many smaller ones. The parotid glands, submandibular
glands and sublingual glands are the large,
paired salivary glands. The parotids are located inside the
cheeks, one below each ear. The submandibular glands
are located on the floor of the mouth, with one on the
inner side of each part of the lower jaw, or mandible. The
sublingual glands are also in the floor of the mouth, but
they are under the tongue.

The parotids are the salivary glands most often
affected by tumors. Yet most of the tumors that grow in
the parotid glands are benign, or not cancerous. Approximately
8 out of 10 salivary tumors diagnosed are in a
parotid gland. One in 10 diagnosed is in a submandibular
gland. The remaining 10% are diagnosed in other salivary
glands.

In general, glands more likely to show tumor growth
are also glands least likely to show malignant tumor
growth. Thus, although tumors of the sublingual glands are
rare, almost all of them are malignant. In contrast, about
one in four tumors of the parotid glands is malignant.
Cancers of the salivary glands begin to grow in
epithelial cells, or the flat cells that cover body surfaces.
Thus, they are called carcinomas, cancers that by definition
begin in epithelial cells.

Demographics

About 7% of all cancers diagnosed in the head and
neck region are diagnosed in a salivary gland. Men and
women are at equal risk.

Causes and symptoms

When survivors of the 1945 atomic bombings of
Nagasaki and Hiroshima began to develop salivary gland
tumors at a high rate, radiation was suspected as a cause.
Ionizing radiation is a factor that contributes to tumor
development. So is radiation therapy. Adults who
received radiation therapy for enlarged adenoids or tonsils
when they were children, are at greater risk for salivary
gland tumors.

There seems to be some link between breast cancer
and salivary gland tumors. Women with breast cancer are
more likely to be diagnosed with salivary gland tumors.
Also linked to salivary gland tumors is alcohol use, exposure
to sunlight (ultraviolet radiation) and hair dye use.

There is evidence that people infected with herpes viruses
may be at greater risk for salivary gland tumors. Individuals
infected with human immunodeficiency virus (HIV)
have more salivary gland disease in general, and may be
at greater risk for salivary gland tumors.

Symptoms are often absent until the tumor is large
or has metastasized (spread to other sites). In regular
dental exams, however, the dentist looks for masses on
the palate or under the tongue or in the cheeks, and such
check-ups are a good way to detect tumors early.