Mastocytosis - Diagnosis

Approved by the Cancer.Net Editorial Board, 06/2016

ON THIS PAGE: You will find a list of common tests and procedures that doctors use to find the cause of a medical problem. To see other pages, use the menu.

Doctors use many tests to find, or diagnose, mastocytosis. Doctors may also do tests to learn which treatments could work best.

A biopsy is the only sure way for the doctor to know whether an area of the body has mastocytosis. 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 this condition. Not all tests listed will be used for every person. Your doctor may consider these factors when choosing a diagnostic test:

  • Your signs and symptoms

  • Your age and medical condition

  • The results of earlier medical tests

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

  • Blood and urine tests. The patient’s blood and urine are tested 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. These 2 procedures are similar and 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. Other types of anesthesia may be used to block the awareness of pain.

  • 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 (see Treatment Options).

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. It explains the system doctors use to describe the extent of cancerous conditions. Or, use the menu to choose another section to continue reading this guide.