title: [The diagnosis and differential diagnosis of lymphocytic interstitial pneumonia].
abstract: OBJECTIVE
  To explore the etiology, diagnosis and differential diagnosis of lymphocytic interstitial pneumonia (LIP).
  
  
  METHODS
  The clinical, radiographical and histological characteristics of three cases of LIP diagnosed in Peking Union Medical College Hospital were analyzed, and the literature was reviewed.
  
  
  RESULTS
  The precise cause of LIP was unknown. However, LIP was strongly associated with autoimmune diseases and immunodeficiency. Clinically, patients presented with chronic cough and progressive dyspnea. Pulmonary function tests showed restrictive ventilatory pattern. HRCT of chest revealed ground-glass attenuation, centrilobular nodules, subpleural small nodules, thickening of bronchovascular bundles, interlobular septal thickening and cystic dilated air spaces. Bronchoalveolar lavage showed an increase in lymphocytes. The key finding in histopathology was dense interstitial lymphoid infiltrate with a polyclonal pattern.
  
  
  CONCLUSIONS
  Idiopathic LIP is rare. Cases of LIP should be thoroughly investigated for any known causes and related disorders.
authors.affiliation: Department of Respiratory Medicine, Peking Union Medical College Hospital, Chinese Academy of Medical Science, Beijing 100730, China. qlingxu@yahoo.com.cn
authors.forename: Ling
authors.initials: L
authors.lastname: Xu
authors.forename: Wen-bing
authors.initials: WB
authors.lastname: Xu
authors.forename: Bai-qiang
authors.initials: BQ
authors.lastname: Cai
authors.forename: Yuan-jue
authors.initials: YJ
authors.lastname: Zhu
mesh_terms: D000293:Adolescent; D001327:Autoimmune Diseases / Q000150:complications; D001706:Biopsy; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D007153:Immunologic Deficiency Syndromes / Q000150:complications; D017563:Lung Diseases, Interstitial / Q000175:diagnosis* / Q000209:etiology / Q000473:pathology; D008875:Middle Aged; D012189:Retrospective Studies