This is a childhood disease which occurs infrequently. When it is found in a serious and aggressive form, it has many features of a cancer. On the other hand, the disease can behave in a benign manner. Histiocytes are normally present in different parts of the body such as the blood stream, skin, liver, lungs, lymph glands and spleen. With this disease, the histiocytes proliferate and infiltrate into the neighbouring tissues. Immunological abnormalities have been described in association with this disease and it has led to the suggestion that Langerhans cell histiocytosis may be a disorder of the immune system.
The aggressiveness of the disease seems to be related to the age of the patient. In children under the age of 2, there is often widespread involvement of the skin, resulting in a seborrhoeic rash. The scalp and the skin behind the ears are most characteristically involved. In addition, there is frequent swelling of the lymph glands. The liver and the spleen are usually enlarged, giving rise to a distended abdomen. There may be anaemia due to bone marrow involvement, and shortness of breath due to lung involvement.
In older children between the ages of 2 and 8, the disease tends to be less aggressive and usually involves the bone and soft tissue. Any bone in the body may be involved, but the skull bone is frequently eroded and the external ear is often inflammed. Sometimes, the disease affects the secretion of hormone of the pituitary gland and then the child passes a lot of urine and is thirsty all the time. This is called diabetes insipidus.
In children above the age of 8, the disease is usually localized and appears as single or multiple bone lesions.
The diagnosis of Langerhans cell histiocytosis is confirmed by tissue biopsy of the skin or the bone. Biopsy of the lymph glands or the liver may sometimes be required. The results of blood tests and bone marrow aspiration will indicate whether or not the bone marrow has been involved, and X-rays of bones and lungs will show whether these organs are affected.
Treatment of Langerhans cell histiocytosis depends on the severity of the disease, and the nature and number of organs (bone marrow, lungs or liver) involved. Isolated asymptomatic lesions may disappear naturally without any treatment. However, when the lesion causes symptoms such as pain, treatment by surgery, local irradiation or local injection of steroid may be required. If the disease is extensive, particularly if it causes organ dysfunction, or if the child has fever or is losing weight, treatment by chemotherapy is needed.
As many as 80 percent of children with Langerhans cell histiocytosis recover either naturally or with treatment. The disease can be aggressive, resulting in death, especially in children under 1 year old. The older the child, the higher the chance of recovery. It is unusual for the disease to recur. But some patients may have residual problems such as ear discharge, deafness, or diabetes insipidus.