Pulmonary Langerhans Cell Histiocytosis
Describe the salient epidemiologic, clinical, physiologic, and radiographic features of Langerhans cell histiocytosis, lymphangioleiomyomatosis, and cryptogenic organizing pneumonia.
Compare and contrast the salient features seen on high-resolution CT scans in these disorders.
Review the characteristic histopathologic features of each of these disorders, and the role of immunohistochemical techniques or markers (for pulmonary Langerhans cell histiocytosis and lymphangioleiomyomatosis).
Review the differing therapeutic strategies for these disorders.
Pulmonary Langerhans cell histiocytosis (PLCH; also termed Langerhans cell granulomatosis) and lymphangioleiomyomatosis (LAM) are rare and poorly understood chronic lung disorders characterized by extensive cyst formation within the lung parenchyma. These disorders share certain features, but LAM affects exclusively women, while PLCH may affect either sex and almost exclusively occurs in smokers. Cryptogenic organizing pneumonia (COP), formerly termed bronchiolitis obliterans organizing pneumonia (BOOP), is a rare disease of unknown etiology characterized by dense alveolar infiltrates, subacute course, and excellent responsiveness to corticosteroid (CS) therapy. This chapter reviews the salient features of these disorders and presents approaches to diagnosis and therapy.