A. What is LCH?
Langerhans Cell Histiocytosisi (LCH) is a rare disease that occurs most often in children, with the maximum incidence between the ages of 1-3 years, without racial preference, with an incidence of approximately one case per 200,000 children per year, a frequency similar to that of Hodgkin’s Lymphoma or acute myelogenous leukemia and a male-female ratio of 2: 1. The chance of occurring in adults is more rare and is characterized as an “orphan disease”, with an estimated incidence of 1-2 cases per 1,000,000 per year and an average age at diagnosis of 33 years. Especially for Greece, the annual incidence of the disease in adults has recently been calculated and is 1.6 new cases per 1,000,000 population per year.
The disease first appeared in the medical literature at the beginning of the 20th century. Although doctors have written a lot about the disease in the past, it is in recent years that it has attracted intense attention and interest. Histiocytes are a class of cells found in the human body. Their function is to help destroy certain foreign elements and fight infection. For some unknown reason, patients with the disease have many more histiocytes (Langerhans cells from the name of the Austrian biologist he discovered). These cells accumulate in specific areas of the body and cause various serious or less serious problems. LCH disease is also known as: Histiocytosis-X Eosinophilic granuloma Hand-Schuller-Christian syndrome Letterer-Siwe disease There are also a number of terms used to describe syndromes that are considered to be LCH. These include: Reticuloendothelial disease, Hashimoto-Pritzker syndrome, Self-healing histiocytosis, Pure dermal histiocytosis, Langerhans cell granulomatosis, Type II histiocytosis, etc.
B. What causes LCH?
The cause is still largely unknown. It can be caused by an unusual reaction of the immune system and/or by an inherited genetic mutation. It is not a known infection nor does it belong to the category of cancers. So far no inheritance has been proven in the transmission of the disease between generations. Patients are not infected by anyone and cannot infect anyone else.
C. What kind of problems can arise?
A patient may have limited involvement in only one part of the body (single system disease) or in several different areas (multisystem disease or multifocal single system disease). Usually, the disease is more serious when several parts are infected.
Possible locations include:
Bones (single or multiple lesions)
Lung, liver, spleen (dysfunction, cirrhosis)
Teeth and gums (loose or falling teeth, swollen gums)
Ears (chronic diseases or discharge)
Eyes (vision problems, swelling)
Central nervous system (encephalitis, mobility disorders, difficulty in memory / learning / communication – excessive thirst and urination)
General symptoms such as fever, weakness, insufficient weight gain, lack of muscle strength / growth may also occur.
D. What tests are done for the disease?
The diagnosis of LCH is usually made after biopsy and microscopic examination of the affected tissue, which may be skin, bones, lymph nodes, etc. The diagnosis of the disease can not be supported without confirmation from biopsy material and therefore radiological diagnoses that refer to LCH can not be accepted as confirmatory of the disease, as the risk of misdiagnosis is extremely high. To determine the extent of the disease and the treatment plan to be followed, various other tests must be done. Some of these are blood tests, x-rays, CT and MRI scans, scintigraphs, pet scans, etc. It may also be necessary from time to time to have a new biopsy of an infected tissue to confirm that it is a new outbreak of the disease and not another entity that simply coexists with
E. What is the treatment for the disease?
There is no etiological treatment for LCH disease and therefore no definite cure can be given for the disease. In cases where the disease is multisystem with involvement of various organs and systems (eg skin, bones, lungs, etc.), as well as in cases where the disease affects a single system (involvement of only one system, eg skin) but with multifocal lesions or / and the involvement of a vital organ (bone marrow, liver, spleen, central nervous system) systematic chemotherapy is the optimal therapeutic intervention. Immunosuppressive therapies, such as methotrexate and azathioprine, can often be chosen among adult patients with mild symptoms. In particular, in the case of single system LCH disease, with unifocal bone involvement of the facial bones, which are characterized as “harmless” to the CNS, lesional treatment and / or occasional treatment with bisphosphonates or denosumab and careful monitoring due to the increased likelihood of diabetes insipidus as well as of other hormonal disorders from the pituitary gland. Complete resection / removal of organic bone lesions is not indicated, as it may increase the size of the bone defect and the time of treatment or may lead to permanent skeletal defects. Injecting cortisone into the area of the lesion may sometimes speed up healing. Radiation therapy is indicated in case of imminent risk of neurological damage and a high risk from a surgical intervention, e.g. damage of the C2 vertebra or the base of the skull. For cases of multifocal bone LCH disease and of bone lesions in “specific areas”, systemic treatment is recommended. Both the optimal duration of treatment and the best combination of drugs to reduce the high risk of relapse in patients with the disease are not yet known.