Anatomy of the thymus gland. The thymus gland is a small organ that lies in the upper chest under the breastbone. It makes white blood cells, called lymphocytes, which protect the body against infections.
There are different types of tumors
of the thymus. Thymomas
and thymic carcinomas
are rare tumors of the cells
that are on the outside surface of the thymus. The tumor cells in a thymoma look similar to the normal cells of the thymus, grow slowly, and rarely spread beyond the thymus. On the other hand, the tumor cells in a thymic carcinoma look very different from the normal cells of the thymus, grow more quickly, and have usually spread to other parts of the body when the cancer
is found. Thymic carcinoma is more difficult to treat than thymoma.
Signs and symptoms of thymoma and thymic carcinoma include a cough and chest pain.
Thymoma and thymic carcinoma may not cause early signs
or symptoms. The cancer may be found during a routine chest x-ray. Signs and symptoms may be caused by thymoma, thymic carcinoma, or other conditions. Check with your doctor if you have any of the following:
A cough that doesn't go away.
Chest pain.
Trouble breathing.
Tests that examine the thymus are used to detect (find) thymoma or thymic carcinoma.
The following tests and procedures may be used:
Physical exam
and history: An exam of the body to check general signs of health, including checking for signs of disease, such as lumps or anything else that seems unusual. A history of the patient’s health habits and past illnesses and treatments will also be taken.
Chest x-ray: An x-ray
of the organs and bones inside the chest. An x-ray is a type of energy beam that can go through the body and onto film, making a picture of areas inside the body.
CT scan
(CAT scan): A procedure that makes a series of detailed pictures of areas inside the body, such as the chest, taken from different angles. The pictures are made by a computer linked to an x-ray machine. A dye
may be injected
into a vein
or swallowed to help the organs or tissues show up more clearly. This procedure is also called computed tomography, computerized tomography, or computerized axial tomography.
MRI
(magnetic resonance imaging): A procedure that uses a magnet, radio waves, and a computer to make a series of detailed pictures of areas inside the body, such as the chest. This procedure is also called nuclear magnetic resonance imaging (NMRI).
PET scan
(positron emission tomography scan): A procedure to find malignant
tumor cells in the body. A small amount of radioactiveglucose
(sugar) is injected into a vein. The PET scanner
rotates around the body and makes a picture of where glucose is being used in the body. Malignant tumor cells show up brighter in the picture because they are more active and take up more glucose than normal cells do.
Thymoma and thymic carcinoma are usually diagnosed, staged, and treated during surgery.
A biopsy
of the tumor is done to diagnose
the disease. The biopsy may be done before or during surgery
(a mediastinoscopy
or mediastinotomy), using a thin needle to remove a sample of cells. This is called a fine-needle aspiration (FNA) biopsy. Sometimes a wide needle is used to remove a sample of cells and this is called a core biopsy. A pathologist
will view the sample under a microscope
to check for cancer. If thymoma or thymic carcinoma is diagnosed, the pathologist will determine the type of cancer cell in the tumor. There may be more than one type of cancer cell in a thymoma. The surgeon
will decide if all or part of the tumor can be removed by surgery. In some cases, lymph nodes
and other tissues may be removed as well.
Certain factors affect prognosis (chance of recovery) and treatment options.
The prognosis
(chance of recovery) and treatment options depend on the following:
