What is Histiocytosis in Children?
Histiocytosis in children is a group of diseases that are quite rare in medical practice, proceed in different ways, but are combined by proliferative processes in the monocytic-macrophage system. Histiocytosis can be both a systemic neoplasm, and can be expressed in the formation of benign single granulomas.
Histiocytes are part of the reticuloendothelial system, on which the response of the child’s immunity to a meeting with the infection depends. Histiocytosis in a child is divided into 3 groups:
- Langerhans cell (from Langerhans cells)
- Virus-associated hemophagocytic syndrome
Accurate morbidity statistics are not known, but it is estimated that there are 1 case per 1 million children under the age of 15. In adults, the incidence is even lower. They diagnose the disease on average at the age of 3 years. Boys get sick a little more often than girls.
Some researchers believe that langerhans cell histiocytosis in children is a malignant disease, while others consider this form of histiocytosis as a non-tumor process.
With malignant histiocytosis, a high mortality rate. It happens in babies up to 3 years. Multiple systemic changes occur in the lymph nodes. The disease affects the internal organs, as well as the bones of the skeleton. Skin disorders are typical for this group of diseases. Erythrematous rashes and large scaly brown papules appear, they can soon turn into ulcers.
Hand – Schuller – Christian disease is a variant of histiocytosis that is also rare. This is a systemic disease that progresses slowly. Granulomatous lesions of bone tissue, internal organs, and lymph nodes appear. In the later stages of the disease, a classic triad appears, in which exophthalmos, granulomas in the bones of the skull and diabetes insipidus develop. 1/3 of the cases are typical skin lesions. Dermal infiltrate in the form of relatively large papules appears under the armpits and in the groin.
Localized histiocytosis is known as eosinophilic granuloma, as well as Langerhans cell granuloma. The disease proceeds benignly in patients of different sizes, foci of tissue destruction in the bones develop. They fix the appearance of dense papules and nodular formations that occur in the face and in the hair on the head.
Causes of Histiocytosis in Children
The causes of this disease have not yet been established. It is assumed that the basis of this ailment is the pathology of the processes of immune regulation. In particular, a violation of the interaction of T-lymphocytes and macrophages is considered a possible cause. Another theory is not excluded, according to which certain viruses cause the disease, in particular, the herpes virus type 6. To date, it has been proven that the proliferation process (neoplasm of cells and intracellular structures – mitochondria, endoplasmic reticulum, ribosomes, etc.) of Langerhans cells with histiocytosis X is characterized by a monoclonal (belonging to the same cell clone) character. But convincing evidence of this hypothesis has not yet been obtained.
Pathogenesis during Histiocytosis in Children
This disease is characterized by enhanced proliferation (reproduction of cellular elements) of histiocytes, as well as their accumulation in different tissues and the formation of granulomas. Histiocytic infiltrates also contain plasmocytes, eosinophils, proliferated reticular fibers and lymphocytes, which leads to pneumofibrosis. (Pneumofibrosis is a disease characterized by proliferation of the connective tissue of the lung due to the inflammatory process, which causes a violation of the structure of the lungs and a decrease in their ventilation function. Further pathological process provokes deformation of the bronchi, wrinkling of the lungs and a decrease in their volume). In addition to damage to lung tissue, respiration vessels infiltrate with histiocytes. Later, this leads to the development of fibrosis and the formation of cystic cavities.
Symptoms of Histiocytosis in Children
It is impossible to avoid skin lesions with a generalized form of histiocytosis X. Most often the skin is affected in children. Moreover, the smaller the child, the more often this happens. Clinically, histocytosis is manifested polymorphic and nonspecific. In patients over a long period, seborrheic dermatitis and eczema are observed. Most often, the skin of the scalp and trunk are affected. In these places, papular rashes of brown or whitish color appear, covered with a crust that is covered with ulcers.
Oral mucous membranes can also be affected, as gingival hyperplasia and stomatitis develop. The histological (associated with the microscopic structure of tissues) manifestations of various clinical variants of histiocytosis in their course do not have particularly significant differences. In the skin, infiltrates are located in the surface layers of the dermis. They are most often striped. But at the same time, the formation of nodes is possible. Sometimes manifestations of diffuse infiltration of all layers of the dermis (thick inner layer of the skin lying under the epidermis) can be detected.
Hair follicles and epidermotropism are often found. At an early stage of the lesion, they are similar to an inflammatory granuloma; proliferation of atypical histiocytes is detected. In addition, eosinophils can often be detected in infiltrates. They are especially numerous in the case of eosinophilic granulomas.
Diagnosis of Histiocytosis in Children
You can establish a suspicion of histiocytosis according to the story of the parents and after a careful examination of the child. A general and biochemical blood test is performed to determine the condition of the bone marrow and to check the functioning of the liver. To confirm the diagnosis of diabetes insipidus, a child should do a urine test. Retngenographic methods can detect bone lesions.
Radioisotope scanning of the skeletal system in some cases is useful for obtaining additional information, but in about a third of cases, lesions are not detected.
To detect affected areas using the method of computed tomography. The use of MRI is justified if there is a suspicion of damage to the brain and spinal cord. To establish a final diagnosis and determine the treatment, a biopsy is used – a piece of the tumor is taken for microscopic treatment.
Treatment of Histiocytosis in Children
In acute histiocytosis in children, glucocorticoids are used in combination with cytostatics (chlorobutin, leukeran, vincristine).
Leukeran is used daily at 0.1 mg per 1 kg of the child’s body inside. The course lasts 2 weeks. Then you need to take a break for the same period. Vincristine is taken once a week at 1.5 mg. It takes 10 cycles of treatment. The main therapy is supplemented by symptomatic:
- preparations of the posterior pituitary gland
There is also information about the effective use of thymosin (thymalin) and decaris (levamisole).
Vincristine 1.5 mg, a single dose per week or leukeran 0.1 mg / kg every day, taken orally for 2 weeks, followed by a 2-week break. Such treatment cycles spend about 10.
In case of Hend – Schüller – Christian and Taratynov diseases and unaffected internal organs, less intensive treatment can be performed, but symptomatic preparations are also indicated. Diseases of Taratynov and Hend – Schuller – Christian are more favorable than the diseases of Abt – Letterer – Siwa, which are detected in a timely manner, at the beginning of treatment.
In generalized forms of histiocytosis, an adverse outcome is recorded in 70% of cases. With localized forms, the prognosis is very favorable.