What Is Eosinophilic Granuloma?

Medically Reviewed by Stephanie S. Gardner, MD on February 21, 2024
4 min read

Eosinophilic granuloma (EG) is a type of lesion that usually appears on bones. These lesions are caused by an overgrowth of Langerhans cells, which are naturally occurring white blood cells that are part of your immune system. These cells can malfunction and develop into bone tumors that affect different body parts.

EG is not a common condition. It affects children more often than adults. It can require complex treatment, or it can go away with no treatment at all.

EG is a form of Langerhans cell histiocytosis (LCH). This type of disorder is caused when Langerhans cells, which are part of the immune system, grow too quickly. The cells collect in parts of the body and create lesions and damage surrounding tissue.

Researchers don't know exactly what triggers LCH. There is some evidence that it happens due to a reaction to a viral infection, bacteria, or immune dysfunction. Some types of LCH have some similarities to cancer and respond to cancer treatments. It's currently classified as an inflammatory myeloid neoplasm. It's associated with certain spontaneous gene mutations.

EG is the mildest form of Langerhans cell histiocytosis. With EG, the overactive Langerhans cells accumulate on bone and form harmless lesions. In most cases, there is only one lesion, but multiple bone lesions can form.

The disorder is rare. Experts believe there are only 4 to 5 cases per million each year in children under age 15 years. The incidence for adults is 1 to 2 cases per million each year.

It's more common among Caucasian and Hispanic people. More males than females have EG. It doesn't seem to be an inherited disorder. People with EG tend to have a genetic mutation, which is a spontaneous change to their genes, rather than a trait passed down in families.

EG affects bones, but does not usually appear on soft tissue or organs. The most common location for EG bone lesions is in the skull. They also appear on vertebrae, ribs, jaws, and bones in the arms or legs. The symptoms of EG include:

  • Pain or tenderness around the affected bone
  • Swelling around the affected bone 
  • Headache
  • Fever 
  • Fracture in the affected bone

Your doctor will need to do multiple tests to diagnose EG. You may need blood tests, imaging tests such as X-rays or MRIs, or a biopsy to study the lesion itself. It's important to rule out other conditions such as bone cancer

Your doctor may also suggest genetic testing. LCH conditions are often linked to certain genetic mutations. Identifying the genetic cause of your EG can help your doctor choose the best treatment for you.

Eosinophilic granuloma treatment depends on the location of the lesions and how they are affecting your life and overall health. 

Watchful waiting. Not all people who have EG need treatment. If the lesion isn't causing significant problems, your doctor may suggest waiting and monitoring it. You will get periodic imaging tests to look for changes. Doctors have found that some EG lesions go away over time without treatment. 

Immobilization. If a lesion is on the spine, your doctor may prescribe a brace to immobilize the bone. This measure may prevent damage to the vertebrae. Doctors find that immobilizing the spine helps the bone in the area reconstitute.

Steroids. If you have pain from the lesions, your doctor might suggest steroid injections. Steroids are common treatments for pain. The injections can help you feel more comfortable.

Surgery. If the lesion is affecting bone health or causing significant pain, you might need surgery. Your doctor will remove the lesion while you are under general anesthesia. 

Most people who have a single EG lesion have a good prognosis. The lesions tend to respond to treatment, or they go away without intervention. The most common complication is bone fracture.

During the process of diagnosing the cause of a bone lesion, your doctors may realize that you have a more severe form of LCH. There may be additional bone lesions, or other organs might be affected.

If this happens, your treatment plans might be more complicated. Depending on the exact diagnosis, you may need radiation, chemotherapy, or surgery. Your doctor will be able to explain your diagnosis and treatment to you.

If you have EG and recover, you are unlikely to have a recurrence. It is also unlikely that you will pass the condition to your children in the future. If you have questions about EG, ask your doctor for information.