Mastocytosis: Diagnosis

Approved by the Cancer.Net Editorial Board, 05/2015

ON THIS PAGE: You will find a list of the common tests and procedures that doctors can use to find out what’s wrong and identify the cause of the problem. To see other pages, use the menu on the side of your screen.

Doctors use many tests to diagnose a disease and find out its extent. Some tests may also determine which treatments may be the most effective. A biopsy is the only way to make a definitive diagnosis of mastocytosis. If a biopsy is not possible, the doctor may suggest other tests that will help make a diagnosis.

This list describes options for diagnosing this condition, and not all tests listed will be used for every person. Your doctor may consider these factors when choosing a diagnostic test:

  • Age and medical condition

  • Type of disease suspected

  • Signs and symptoms

  • Previous test results

In addition to a physical examination, the following tests may be used to diagnose mastocytosis:

  • Blood/urine tests. Tests are done on samples of the patient’s blood and urine to help find high levels of mast cells and histamine. Blood tests can also show how well the liver, kidneys, and other organs are working. The blood’s level of an enzyme called tryptase may be higher than normal for people with systemic mastocytosis. However, a high level of tryptase may also occur as a result of other non-cancerous or reactive conditions.

  • Biopsy. Skin biopsies are often used to diagnose mastocytosis. A biopsy is the removal of a small amount of tissue for examination under a microscope. Other tests can suggest that mastocytosis is present, but only a biopsy can make a definite diagnosis. A pathologist then analyzes the sample(s) removed during the biopsy. A pathologist is a doctor who specializes in interpreting laboratory tests and evaluating cells, tissues, and organs to diagnose disease.

  • Bone marrow aspiration and biopsy. Bone marrow aspiration and biopsy are similar procedures and are often done at the same time to examine the bone marrow. Bone marrow has both a solid and a liquid part. A bone marrow aspiration removes a sample of the fluid with a needle. A bone marrow biopsy is the removal of a small amount of solid tissue using a needle. A pathologist then analyzes the sample(s) to help diagnose systemic mastocytosis.

    A common site for a bone marrow aspiration and biopsy is the pelvic bone, which is located in the lower back by the hip. The skin in that area is numbed with medication beforehand, and other types of anesthesia (medication to block the awareness of pain) may be used.

  • Molecular testing. Your doctor may recommend running laboratory tests on tissue samples to identify specific genes, proteins, and other factors unique to the mast cells. Results of these tests will help decide whether your treatment options include a type of treatment called targeted therapy.

After these diagnostic tests are done, your doctor will review all of the results with you. If the diagnosis is mastocytosis, these results will help the doctor identify the type and plan treatment.

The next section in this guide is Stages, and it explains the system doctors use to describe the extent of cancerous conditions. Or, use the menu on the side of your screen to choose another section to continue reading this guide.