Skip Navigation

Visiting Dana-Farber? See our prescreening and mask requirements.

How We Diagnose Histiocytosis

  • Biopsy

    At the Adult Histiocyte Disorders Center of Dana-Farber Brigham Cancer Center, your biopsies are always reviewed by one of our expert pathologists. These specialists consider all of the diagnostic information available, combined with clinical information provided by your doctor, to make an accurate diagnosis.

    Langerhans cell histiocytosis (LCH), Erdheim-Chester disease (ECD), and histiocytic sarcoma (HS) can be definitively diagnosed only based on a biopsy. Because these are rare diseases, having the biopsy reviewed by a pathologist with experience in these disorders is critically important.

    The first step in diagnosing a histiocyte disorder is examining the biopsy with a microscope. These diseases often have very characteristic appearances. For instance, ECD is often characterized by large cells filled with lipids (fats), while HS is often spindle-shaped.

    If you would like a second opinion...

    Our diagnostic team provides second opinions and we are happy to consult with you, your primary care physician, or other specialists. You may want to consider a second opinion:

    • To confirm your diagnosis
    • To have original biopsies or other tissue diagnosis confirmed
    • For details on your type of histiocytosis
    • To better understand your treatment options
    • To learn if you are eligible for clinical trials

    Phone: 877-442-DFCI or 877-442-3324
    Online: Complete the Appointment Request Form
    If you cannot travel to Boston in person, you can take advantage of our Online Second Opinion service

    Genetic analysis

    The appearance of the cells alone, however, is not enough to make a diagnosis – it is only a clue.

    Each histiocyte disease can be characterized by the presence or absence of certain proteins and molecules. Differentiating among the different proteins and molecules involved can get very complicated, and requires a high level of expertise.

    Recently, specific genetic alterations have been identified in LCH and ECD. In fact, the first genetic mutation in LCH, in a gene called BRAF, was discovered at Dana-Farber. The genetic mutation has since been described in ECD. Other mutations have also been described in LCH, including mutations in genes called ARAF, MAP2K1 and PIK3CA.

    We perform gene testing and use this information to help us make a diagnosis of a histiocyte disorder and to look for new causes of these rare diseases.


    Radiology is also important in the diagnosis and management of histiocyte disorders:

    • Diseases such as LCH often have characteristic findings on radiology tests. For instance, LCH frequently affects the pituitary gland; this can be discovered by careful analysis of an MRI (magnetic resonance imaging), or by areas of missing bone (called lytic lesions), which can be seen on X-ray or CT (computed tomography) scan.
    • LCH occurring in the lungs of smokers commonly causes small nodules in the upper part of the lungs and strangely shaped cysts in the lung. ECD often causes tell-tale scarring in the bones (osteosclerosis) that can be detected on bone scans or PET (positron emission tomography) scans. ECD also can cause a fuzzy appearance around the kidney (so-called "hairy kidney").
    • Increasingly, we use PET scans in the diagnosis and management of these diseases. A PET scan measures metabolic activity based upon how much sugar cells are using. Cancer cells – including histiocyte disorders – generally have a higher metabolic rate than normal cells and can sometimes be detected on PET scan when they cannot be seen on a CT scan.

    Lab testing

    Laboratory testing is also important in making the diagnosis and determining the effects of histiocyte disorders on the body.

    • Specialized blood and urine tests can detect involvement of the pituitary gland before there are symptoms, and sometimes before the disease can be seen on an MRI.
    • A urine test can look for evidence of a mutation in the BRAF gene in the DNA in your urine.

    In our Center, we are collaborating with researchers in the lab to develop blood tests for various genes that are important in the development of histiocyte disorders. Our goal for these tests is to help us make ever more accurate diagnoses and follow the progress of the disease.