ON THIS PAGE: You will find a list of common tests, procedures, and scans that doctors use to find the cause of the medical problem. To see other pages, use the menu.
Doctors use many tests to find, or diagnose, a tumor. They also do tests to learn if the tumor has spread to another part of the body from where it started. If this happens, it is called metastasis. For example, imaging tests can show if the tumor has spread. Imaging tests show pictures of the inside of the body. Doctors may also do tests to learn which treatments could work best.
For most types of cancer, a biopsy is the only sure way for the doctor to know whether an area of the body has cancer. In a biopsy, the doctor takes a small sample of tissue for testing in a laboratory. If a biopsy is not possible, the doctor may suggest other tests that will help make a diagnosis.
This list describes options for diagnosing PPB, and not all tests listed will be used for every person.
The diagnosis of PPB depends on an examination under a microscope of material from inside the chest, either cyst material or solid tumor tissue. In Type I, or cystic, PPB, the cysts appear only slightly abnormal, but very close evaluation shows that the walls of the cysts contain very small collections of cancerous cells. In Types II and III PPB, it is obvious when looking under a microscope that tissue inside the chest is cancerous, but because PPB is so rare, it may be difficult for the doctors to determine exactly what type of tumor it is. In Types II and III PPB, it can spread to the heart so doctors might also check the great vessels of the heart and the chest cavity as well. Often, doctors will send tissue samples to other experts for help determining the correct diagnosis.
In addition to a physical examination, the following tests may be used to diagnose PPB:
Biopsy. A biopsy  is the removal of a small amount of tissue for examination under a microscope. Other tests can suggest that a tumor is present, but only an examination of a piece of the tumor can make a definite diagnosis. A pathologist then analyzes the sample(s). A pathologist is a doctor who specializes in interpreting laboratory tests and evaluates cells, tissues, and organs to diagnose disease.
X-ray. An x-ray is a way to create a picture of the structures inside of the body using a small amount of radiation.
Computed tomography (CT or CAT) scan. A CT scan  creates a 3-dimensional picture of the inside of the body using x-rays taken from different angles. A computer then combines these images into a detailed, cross-sectional view that shows any abnormalities or tumors. A CT scan can also be used to measure the tumor’s size. Sometimes, a special dye called a contrast medium is given before the scan to provide better detail on the image. This dye can be injected into a patient’s vein or given as a pill to swallow. After a chest x-ray shows something abnormal in the lungs, a CT scan is the best method for obtaining more information.
Magnetic resonance imaging (MRI). An MRI  uses magnetic fields, not x-rays, to produce detailed images of the body. MRI can also be used to measure the tumor’s size. A special dye called a contrast medium is given before the scan to create a clearer picture. This dye can be injected into a patient’s vein or given as a pill to swallow. An MRI is not a very good way to look inside the chest, but it is often the best test for looking at other parts of the body to determine if the tumor has spread.
Bone scan. A bone scan  uses a radioactive tracer to look at the inside of the bones. The tracer is injected into a patient’s vein. It collects in areas of the bone and is detected by a special camera. Healthy bone appears gray to the camera, and areas of injury, such as those caused by a tumor, appear dark.
After diagnostic tests are done, your child’s doctor will review all of the results with you. If the diagnosis is PPB, these results also help the doctor describe the tumor; this is called staging.
The next section in this guide is Stages.  It explains the system doctors use to describe the extent of the disease. Or, use the menu to choose another section to continue reading this guide.