Erdheim-Chester Disease is an extremely rare disorder that can affect many different organs of the body. It is characterized by excessive production and accumulation of specific cells whose normal function is to fight infections. These cells, which are called histiocytes, infiltrate the loose connective tissue of the body. As a result, this tissue becomes thickened, dense and fibrotic. Multiple different organs can be affected. Unless successful treatment is found, organ failure can result.
The majority of Erdheim-Chester Disease patients are diagnosed between the ages of 40-70, although children have been diagnosed. ECD can affect both men and women, with approximately 60% of reported cases affecting men and 40% women.
The cause of ECD is unknown. However, recently ECD has been classified by the World Health Organization (WHO) as a histiocytic neoplasm (type of blood cancer), with more than 50% of patients testing positive for the BRAF V600E mutation. Chronic, uncontrolled inflammation is also a significant component of the disease process. It is believed that the inflammation is the result of the body’s immune response to a more underlying process in the disease, as opposed to being the primary cause of the disease.
Disease involvement may include long bones of the legs and arms, skin, tissues behind the eyes, lungs, brain, pituitary gland, kidney, abdominal cavity, the membrane surrounding the heart, adrenal glands and more rarely other organs. Each patient can have a different combination of organs attacked.
ECD is considered one of the histiocytic diseases and is often described as a rare multi-system, non-Langerhans Cell histiocytosis.
There have been a very limited number of published cases of ECD in the world since it was first described in the literature in 1930 by the Austrian pathologist, Jakob Erdheim, and the American pathologist, William Chester. Because ECD is so rare and because it is not discussed in the common textbooks of medicine, many doctors have never heard of it. It is also considered difficult to diagnose. For these reasons, most feel the disease may be under-diagnosed. However, the rate of diagnosis appears to be increasing in recent years.
Most published articles on ECD are anecdotal in nature because studies have historically been extremely difficult due to the small and geographically dispersed ECD patient population. However, as patients have joined together in the ECD Global Alliance and ECD Referral Care Centers have been formed, this is now changing. Studies and clinical trials for ECD patients are now becoming available.
The prognosis is variable and depends mainly on the extent and distribution of the disease. It reaches from asymptomatic bone lesions to multi-systemic life-threatening forms. Scientific literature, mainly published before the year 2000, often reports a very poor prognosis but treatment has improved since. Due to this, mortality has considerably decreased. It is important to know there are patients who are living high quality lives with ECD for decades. However, effective treatment and monitoring is required.
Last updated: November 4, 2016