What Is Eosinophilic Granuloma?

Eosinophilic granuloma is a benign bone tumour that develops on bones or organs due to excessive eosinophils in cells. It is most common in children and young adults.

In this article, we will go through the potential causes and symptoms, diagnosis and treatment of this condition.

Overview

Eosinophils are a type of white blood cell that is involved in the immune response and are programmed to kill foreign pathogens (something that can cause disease in people). 

Granuloma is a cluster of white blood cells.  Many think that a cluster of cells automatically refers  to cancerous tumours, however, this is not the case. Granulomas simply form at a site of inflammation, triggering an immune response.

Eosinophilic granuloma affects bones but it can also affect organs, such as skin, lungs, brain, and liver to name a few.

There are two classifications of eosinophilic granuloma:¹

• Monostotic, affecting a single bone
  • Most common and seen in 90% of diagnosed patients
• Polyostotic, affecting multiple sites
  • Seen in almost 10% of diagnosed patients

Eosinophilic granuloma is one of the mildest subtypes of a group of diseases called Langerhans cell histiocytosis.² Langerhans cells are immune cells found in our skin that alert the rest of our immune system to harmful substances. These types of cells are one of the first steps to an immune response. 

Causes of eosinophilic granuloma

The cause  of eosinophilic granuloma is unknown. However, it is known that this condition is not inherited from family members but a change in genes can cause accumulation of eosinophils. 

A benign tumour  is always associated with an abnormal change in the protein that controls the life and death of cells. The change causes the cells to live and grow for a longer period of time, leading to this accumulation of immune cells. This occurrence can happen in either soft tissue, such as organs, or in bones.

In relation to the lungs, the accumulation of Langerhans cells, although rare, is thought to occur due to cigarette smoke exposure.

This condition is most common in children over five and young adults.²

Signs and symptoms of eosinophilic granuloma

There are many potential symptoms of eosinophilic granuloma depending on the area affected and the severity of the disease. Some commonly reported symptoms of eosinophilic granuloma include:²

• Swelling and tenderness around the bone
• Limping if the lower body is affected
• Potential neurological damage if the spine is affected
• Fracture in the affected bone
• Headache
• Fever that persists despite antibiotic treatment
• Increased urination
• Back pain or stiffness
• Change in posture
• Hearing loss or ear mass if the ear is the affected area
• Jaw pain, loose teeth or jaw mass if the jaw is the affected area

If the affected area is the lungs, the patient could present with no symptoms at all or could include

• Weight loss
• Persistent cough
• Chest pain
• Fatigue
• Pneumothorax 

Management and treatment for eosinophilic granuloma

Eosinophilic granuloma comes with several optional treatments.  Surgical and non-surgical methods are recommended interventions. The surgery option  If intervention is required, surgery is preferred to remove the clump of cells. Other treatments can include:²

• Chemotherapy
• Radiation
• Corticosteroids
• Immobilise the affected bone if there is a lesion

Sometimes, patients do not require treatment or intervention. The granuloma may be monitored and can resolve on its own or be triggered to resolve by puncturing it with a biopsy needle injected by a doctor.

Many surgeries can be employed depending on the severity and area affected in the body. Some of these include:

• Curettage - removing or shaving down the bone to activate the bone to heal
• Bone grafting - taking part of a healthy bone and applying it to the affected bone to help repair it
• Lung transplantation if the lung is severely damaged and unrepairable

Diagnosis

For proper diagnosis, doctors must conduct what is called a histopathological examination. This exam is where the physician takes a small sample of the tumour using the manual rotary microtome. The machine slices the tumour cells to observe individual cells. 

They can then use dyes to identify cell shape and type of cells. The method is to distinguish  different immune cells; looking for a certain level of cell expression that are characteristic of eosinophilic granuloma. The physician may require a blood count to evaluate the amount and type of immune cells to rule out similar presenting conditions. X-rays and CT scans visualise the bones to look for lesions and misshapen bones to identify the affected area.Depending on the area affected, other tests could include a lung function test, visual or auditory testing, or a neurological examination.³

Risk factors

There are a number of risk factors that can contribute to the accumulation of immune cells or more specifically Langerhans cells that contribute to the characterisation of the disease.

• Smoking is shown to extremely exacerbate the disease progression in those with pulmonary (lung) eosinophilic granuloma. Studies show that those who cease smoking are more likely to stabilise or even regress the disease.¹
• Age is nearly always a risk factor associated with diseases. The older we get, the more difficult it is to fight off the illness.
• Multi-organ involvement increases the risk and complexity of the disease compared to a single organ or bone involvement. 

Complications

Depending on the affected area, eosinophilic granuloma has many potential complications. Because this disease usually affects the bones and happens to be more common in children and young adults, there is a chance of disrupting regular growth and development. There is also a possibility of permanent disability or restrictive motion. If the affected area is related to the ears or eyes, there could be impairment of vision and hearing. 

As with many diseases, there is a high possibility of negative impact on a patient's emotional state. Patients may be more likely to develop depression or anxiety from being in a hospital setting and continued treatment. It is important to have support from loved ones or healthcare professionals.³

FAQs

How can I prevent eosinophilic granuloma

There is no known way to prevent eosinophilic granuloma. Smoking is associated with several  diseases, including eosinophilic granuloma. For the general health of yourself, it is best to cease tobacco smoking.

How common is eosinophilic granuloma?

It has been reported to be 4 to 5 cases per million in children 15 or younger. In adults, it is reduced to 1-2 cases per million.¹ 

When should I see a doctor?

Should you see any of the above mentioned symptoms, you should visit your doctor as soon as possible in order to get the disease ruled out or caught early. 

Summary

Eosinophilic granuloma is a rare mild subtype of a set of diseases called Langerhans cell histiocytosis. This condition is characterised by an accumulation of a type of white blood cell called eosinophils. This accumulation causes a mass or tumour that affects bones and organs. A majority of cases reportedly affect one area. This disease mostly affects children and young adults with a high recovery rate. Symptoms of this disease are depending on what is affected. In the case of affected bones, it can cause pain in the affected area, poor posture, hearing or vision loss. Although rare, in some cases this disease affects the lungs which is more difficult to treat. Diagnosis is done through X-ray visualisation, blood tests, and a biopsy. Treatment includes both surgical and non-surgical methods of eradicating the cell mass, repairing the bone, or as severe as lung transplantation if the lung is irreparable.