Langerhans'-cell histiocytosis in adults.

Guided by a long-term retrospective observation, the clinical course and treatment of Langerhans'-cell histiocytosis (LCH) in adult patients are represented. The series included 19 patients meeting the histopathologic criteria of presumptive LCH who were followed for 1.5-20 years (average 7.7 years). Most frequently, skeletal lesions (16 patients), diffuse interstitial lung infiltrates (seven patients), and pituitary gland involvement with diabetes insipidus (four patients) were present. Bone lesions of the skull and axial skeleton were associated with an infiltration of adjacent soft tissues in 10 of 16 patients. Liver, lymph node, and bone marrow involvement appeared sporadically. LCH was divided into localized or multifocal form. Localized disease took a benign course with remission of bone (n = 4) or lymph node lesions (n = 2). Also, in isolated pulmonary LCH (n = 2), spontaneous transition to inactive disease occurred. With the exception of isolated bone lesions (n = 27), which remained asymptomatic or showed a remission to treatment, multifocal LCH had a more aggressive course. Osseous lesions with adjacent soft tissue infiltration (n = 20) showed a relapse rate in excess of 80% independent of the treatment applied. Pulmonary involvement led to a more marked functional impairment compared to the isolated form, and systemic treatment yielded no convincing effect. In three patients with liver or bone marrow involvement, LCH showed a persistent, serious disease activity. One patient died of transition into acute monomyelocytic leukemia 18 months after diagnosis without preceding chemotherapy. In adults, LCH seems to be limited to a few organ systems. Multifocal LCH represents the more aggressive form with unfavorable prognosis in patients with bone lesions spreading into the adjacent soft tissue and liver or bone marrow involvement.