Introduction. Langerhans cell histiocytosis encompasses a group of disorders
of unknown origin with different clinical presentations and outcomes. It is
characterized by infiltration of the involved tissues by large numbers of
Langerhans cells, often organized into granulomas. The accumulation of these
cells causes the classic lytic bone lesions, skin rashes, lymphadenopathy,
splenomegaly, and dysfunction of organ such as the pituitary gland, lungs,
liver, and bone marrow. Pulmonary histiocytosis. Adult pulmonary Langerhans
cell histiocytosis is a rare disorder of unknown etiology. It occurs
predominantly in male smokers, with an incidence peak between 20 and 40 years
of age. High-resolution computed tomography of the chest can show nodules,
cavitated nodules, and thickand thin-walled cysts. The definite diagnosis of
pulmonary Langerhans cell histiocytosis requires identification of
Langerhans? cell granulomas infiltrating and destroying distal bronchioles,
which is usually achieved by lung biopsy at a site selected by chest
high-resolution computed tomography. Treatment. Treatment options for adults
have never been clarified by a clinical trial. The published literature
provides minimal data on the comparative efficacy of various treatment
options which include surgery/curettage, steroids, radiation, and various
chemotherapy regimens. The improved understanding of the mechanisms involved
in the pathogenesis of pulmonary Langerhans cell histiocytosis should help in
the development of specific therapeutic strategies and effective treatment.
A Case of Pulmonary Langerhans Cell Histiocytosis with BRAF V600E-negative and MAP2K1-posivtive Mutations Presenting as Diffuse Nodules in Chest High-resolution Computed Tomography After Smoking Cessation
