Diagnosing mesothelioma is often difficult, because the symptoms are
similar to those of a number of other conditions. Diagnosis begins with
a review of the patient's medical history, including any history of
asbestos exposure. A complete physical examination may be performed,
including x-rays of the chest or abdomen and lung function tests. A
CT (or CAT) scan or an MRI may also be useful. A CT scan is a series
of detailed pictures of areas inside the body created by a computer
linked to an x-ray machine. In an MRI, a powerful magnet linked to a
computer is used to make detailed pictures of areas inside the body.
These pictures are viewed on a monitor and can also be printed.
A biopsy is needed to confirm a diagnosis of mesothelioma. In a biopsy,
a surgeon or a medical oncologist (a doctor who specializes in diagnosing
and treating cancer) removes a sample of tissue for examination under
a microscope by a pathologist. A biopsy may be done in different ways,
depending on where the abnormal area is located. If the cancer is in
the chest, the doctor may perform a thoracoscopy. In this procedure,
the doctor makes a small cut through the chest wall and puts a thin,
lighted tube called a thoracoscope into the chest between two ribs.
Thoracoscopy allows the doctor to look inside the chest and obtain tissue
samples. If the cancer is in the abdomen, the doctor may perform a peritoneoscopy.
To obtain tissue for examination, the doctor makes a small opening in
the abdomen and inserts a special instrument called a peritoneoscope
into the abdominal cavity. If these procedures do not yield enough tissue,
more extensive diagnostic surgery may be necessary.
If the diagnosis is mesothelioma, the doctor will want to learn the
stage (or extent) of the disease. Staging involves more tests in a careful
attempt to find out whether the cancer has spread and, if so, to which
parts of the body. Knowing the stage of the disease helps the doctor
plan treatment.
Mesothelioma is described as localized if the cancer is found only
on the membrane surface where it originated. It is classified as advanced
if it has spread beyond the original membrane surface to other parts
of the body, such as the lymph nodes, lungs, chest wall, or abdominal
organs.