Etiology Rheumatoid arthritis (RA) is an autoimmune disorder of unknown cause with variable clinical manifestations. Genetic factors play a major role in disease susceptibility and expression. The B lymphocyte is important in the pathogenesis of RA, and therapeutic B-cell depletion…
Metabolic and storage lung diseases are a broad group of diseases and syndromes characterized by underlying biochemical or metabolic dysfunctions. Accurate diagnosis is difficult because these diseases are often indolent, are rarely encountered in clinical practice, and because their manifestations…
Eosinophilic diseases of the lung include a heterogeneous group of pulmonary disorders that characteristically feature peripheral or tissue eosinophilia. Patients with these illnesses have a variable clinical presentation and may be asymptomatic or may exhibit organ dysfunction or clinical symptoms…
Amitani and colleagues first described a unique pattern of upper lobe–predominant, idiopathic pulmonary fibrosis (IPF) in 13 patients in the Japanese literature in 1992. The currently preferred term in the English-language literature, idiopathic pleuroparenchymal fibroelastosis (iPPFE), was coined by Frankel…
Etiology Lymphangioleiomyomatosis (LAM) is a systemic disease of unknown etiology, affecting almost exclusively women. LAM is characterized by idiosyncratic smooth muscle cell proliferation (LAM cells), which leads to lung cysts, systemic lymphatic abnormalities, and abdominal tumors. The main manifestation is…
Currently, the worldwide number of tobacco smokers is estimated at 1.1 billion people, with the World Health Organization estimating that tobacco use is responsible for approximately 6 million premature deaths each year. In the United States 42 million adults are…
Etiology Langerhans cell histiocytosis (LCH) is an uncommon disease. Several synonyms, including histiocytosis X, eosinophilic granuloma, and Langerhans cell granulomatosis, have been used in the past, but the term Langerhans cell histiocytosis is now preferred. The previously used term histiocytosis…
Etiology Hypersensitivity pneumonitis (HP), also known as extrinsic allergic alveolitis, is an immune-mediated inflammatory form of diffuse interstitial pulmonary disease caused by inhalation of various antigens that affect susceptible patients. Occasionally, an HP reaction pattern may be seen in association…
Sarcoidosis is a systemic inflammatory disorder of unknown etiology that affects multiple organs and is characterized by the formation of noncaseating granulomas. Intrathoracic lymph node and pulmonary parenchymal involvement occurs in more than 90% of cases. The granulomas have a…
Acute interstitial pneumonia (AIP) is a severe acute disease of unknown etiology that usually occurs in a previously healthy individual and produces histologic findings of diffuse alveolar damage. The clinical, radiologic, and pathologic manifestations are identical to those of acute…