Langerhans Cell Histiocytosis Treatment (PDQ®): Treatment - Health Professional Information [NCI] - Presentation of LCH in Children
In LCH, the lung is less frequently involved in children than in adults, because smoking in adults is a key etiologic factor. The cystic/nodular pattern of disease reflects the cytokine-induced destruction of lung tissue. Classically, the disease is symmetrical and predominates in the upper and middle lung fields, sparing the costophrenic angle and giving a very characteristic picture on high-resolution CT scan. Confluence of cysts may lead to bullous formation and spontaneous pneumothorax can be the first sign of LCH in the lung, although patients may present with tachypnea or dyspnea. Ultimately, widespread fibrosis and destruction of lung tissue may lead to severe pulmonary insufficiency. Declining diffusion capacity may also herald the onset of pulmonary hypertension. Widespread fibrosis and declining diffusion capacity are much less common in children. In young children with diffuse disease, therapy can halt progress of the tissue destruction and normal repair mechanisms may restore some function, although scarring or even residual nonactive cysts may continue to be visible on radiologic studies.
Pulmonary involvement is present in approximately 25% of children with multisystem low-risk and high-risk LCH. However, a multivariate analysis of pulmonary disease in multisystem LCH did not show pulmonary disease to be an independent prognostic factor, with a 5-year overall survival rate of 94% versus 96% for those with or without pulmonary involvement.
Most patients with bone marrow involvement are young children who have diffuse disease in the liver, spleen, lymph nodes, and skin who present with significant thrombocytopenia and anemia with or without neutropenia. Others have only mild cytopenias and are found to have bone marrow involvement with LCH by sensitive immunohistochemical or flow cytometric analysis of the bone marrow. A high content of bone marrow macrophages can obscure LCH cells. Patients with LCH who are considered at very high risk sometimes present with hemophagocytosis involving the bone marrow. The cytokine milieu driving LCH is probably responsible for the epiphenomenon of macrophage activation, which in the most severe cases, present with typical manifestations of hemophagocytic lymphohistiocytosis including cytopenias and hyperferritinemia.