The natural history of disease in adult Langerhans cell histiocytosis (LCH), with the exception of pulmonary LCH, is unknown. It is unclear whether there are significant differences from childhood LCH, although it appears that multisystem-risk LCH is less aggressive than childhood high-risk disease. The risk of reactivations is unknown.
Note: The American Joint Committee on Cancer has recently published a new edition of the AJCC Cancer Staging Manual, which includes revisions to the staging for this disease. The PDQ Adult Treatment Editorial Board, which is responsible for maintaining this summary, is currently reviewing the new staging to determine the changes that need to be made in the summary. In addition to updating this Stage Information section, additional changes may need to be made to other parts of this summary to ensure...
It is estimated that one to two adult cases of LCH occur per million population. The true incidence of this disease is impossible to know because large published studies usually are from referral centers and the disorder often is under-diagnosed. A survey from Germany reported that 66% of the LCH patients were women with an average age of 43.5 years for all patients.
Presentation of adult LCH by organ, site, or system
Adult LCH patients may have symptoms and signs for many months before a definitive diagnosis and treatment. LCH in adults is often similar to that in children, and appears to involve the same organs, although the proportions may be different. There is a predominance of lung disease in adults, usually occurring as single-system disease and closely associated with smoking and with some unique biologic characteristics. An ongoing German registry with 121 registrants showed that 62% had single-organ involvement and 38% had multisystem involvement, while 34% of the total had lung involvement. The median age at diagnosis was 44 years � 12.8 years. The most common organ involved was lung followed by bone and skin. All organ systems found in childhood LCH were seen, including endocrine and central nervous system, liver, spleen, bone marrow, and gastrointestinal tract. The major difference is the much higher incidence of isolated pulmonary LCH in adults, particularly in young adults who smoke. Other differences appear to be the more frequent involvement of genital and oral mucosa. There may possibly be a difference in the distribution of bone lesions, but both groups suffer reactivations of bone lesions and progression to diabetes insipidus (DI), although the exact incidence is unknown in adults..
Presenting symptoms from published studies are (in order of decreasing frequency) dyspnea or tachypnea, polydipsia and polyuria, bone pain, lymphadenopathy, weight loss, fever, gingival hypertrophy, ataxia, and memory problems. Among the signs of LCH are skin rash, scalp nodules, soft tissue swelling near bone lesions, lymphadenopathy, gingival hypertrophy, and hepatosplenomegaly. Patients who present with isolated DI should be carefully observed for onset of other symptoms or signs characteristic of LCH. At least 80% of patients with DI had involvement of other organ systems including: bone (68%), skin (57%), lung (39%), and lymph nodes (18%).
Skin and oral mucosa
Thirty-seven percent of adults with LCH have skin involvement which usually occurs as part of multisystem disease. Skin-only LCH occurs but it is less common in adults than in children. The prognosis in adult skin-only LCH is excellent with 100% probability of 5-year survival. The cutaneous involvement is clinically similar to that seen in children and may take many forms.