L’Langerhans cell histiocytosis it is a rare disease which, according to data from the Rare Diseases Observatory – OMAR, has an incidence of 1-2 people in 100,000. It can affect only one organ (in this case it is called monosystemic), such as the lung, skin, bones, mucous membranes, liver, spleen and central nervous system, or extend to multiple organs (multisystemic).
The first symptoms can appear already in early childhood or in adulthood, without distinction in males and females. The age of the patient, as well as the location and spread of the disease, affect prognosis and therapeutic choices. Histiocytosis is a variable disease also in its course over time because it can regress spontaneously or alternate “rest” phases with periods of reactivation.
Langerhans cell histiocytosis: what are the causes?
The causes of this pathology are still unknown and factors that predispose to the disease have not yet been identified. In the pulmonary form, however, there appears to be a link with cigarette smoking.
What is certain is that in the development of histiocytosis, some cells of the immune system play a key role, namely those of Langerhans, which, when defective, proliferate and accumulate in an anomalous way in the various organs, causing the onset of granulomas and of associated symptoms.
What are the symptoms?
Symptoms of Langerhans cell histiocytosis vary depending on the location affected. As the Bambino Gesù Hospital in Rome reportslesions can affect:
Cute. The most affected areas are the skin folds, the head and the trunk. The lesions can appear in the form of papules, vesicles, pustules, ulcers with or without crusts.
Osso. The areas most affected are the skull, long bones, pelvis, flat bones and vertebrae. Swelling with or without pain may occur.
Lymph nodes. It manifests itself with an enlargement of the lymph nodes, especially those in the neck.
Endocrine system. When it affects this system, the disease presents itself with diabetes insipidus, the symptoms of which are high urine output and the sensation of intense thirst.
Central nervous system. Neurological disorders vary according to the affected site but, in general, the patient may experience involuntary movement of the eyes, alteration of speech, loss of coordination of muscle movements.
Digestive system. Symptoms may be vomiting, diarrhea, weight growth retardation.
Mouth. Lesions can affect the mandible, maxillary bone, oral mucosa or teeth.
Langerhans cell histiocytosis: how is the diagnosis made?
There is no specific test. There are various tests that allow the diagnosis to be made: blood and urine tests, genetic research for the BRAF V600E gene mutation, chest and skeletal x-rays, CT and magnetic resonance imaging. Very important, then, is the histological evaluation (by biopsy) of the affected tissue: a pathologist can, in fact, detect an accumulation of Langerhans cells. Once you have the diagnosis, it is essential to go to one of the Disease reference centers to undertake the therapeutic process.
How is it treated?
There is no standard therapy for histiocytosis. The treatment is variable, depending on the organ affected and the extent of the disease. In the absence of symptoms we just tend to monitor the patient. When present, however, therapies are used. As the Rare Diseases Observatory – OMAR reports, currently the most effective drugs are cortisoneemployed in association with chemotherapy (such as vinblastine, vincristine, cytarabine, and cladribine), and some types of anti-inflammatories (indomethacin). For the smoking patient it is essential stop smoking.
The disease must be managed and kept under control throughout life, with regular clinical checks, by a team made up of different specialists. Even when it is in remission, because it could flare up again at any moment or be associated with the development of tumors. In the most serious cases, when therapies are ineffective and life expectancy is reduced, we resort to transplant: lung, liver or bone marrow, depending on the compromised organ.