title: Mechanisms involved in the extension of pulmonary Mycobacterium avium infection from the pulmonary focus to the regional lymph nodes.
abstract: OBJECTIVE
  This study was designed to evaluate the mechanism of Mycobacterium avium extension in lung infection.
  
  
  METHODS
  Retrospective study.
  
  
  METHODS
  A 42-year-old man with acquired immune deficiency syndrome and immune reconstitution inflammatory syndrome. The patient developed mediastinal lymphadenopathy and a peripheral lesion in the right upper lobe within 2 weeks of starting highly active antiretroviral therapy.
  
  
  METHODS
  Pulmonary tissue and lymph nodes were dissected under thoracoscopy and evaluated pathologically and immunohistochemically.
  
  
  RESULTS
  Pulmonary pathologic examination revealed extensive granuloma formation throughout the acini. Mycobacterial antigens were found in the macrophages in the alveoli and in the alveolar septa. Some macrophages including mycobacterial antigens were surrounded by lymphatic endothelial cells in the interstitium. In addition, a proliferative granulomatous lesion was found under the intact epithelial layer of a bronchiole. Pathological examination of the lymph nodes revealed aggregated proliferative granulomas with few mycobacteria. Genetically closely related M. avium strains were isolated from both tissues.
  
  
  CONCLUSIONS
  This study showed the mechanism involved in the progression of pulmonary M. avium infection from the pulmonary focus to the regional lymph nodes via the lymphatic vessels.
authors.affiliation: Department of Infectious, Respiratory, and Digestive Medicine, Control and Prevention of Infectious Diseases, Faculty of Medicine, University of the Ryukyus, Nakagami-gun, Okinawa, Japan. kenjihibiya@gmail.com
authors.forename: Kenji
authors.initials: K
authors.lastname: Hibiya
authors.forename: Masao
authors.initials: M
authors.lastname: Tateyama
authors.forename: Daisuke
authors.initials: D
authors.lastname: Tasato
authors.forename: Hideta
authors.initials: H
authors.lastname: Nakamura
authors.forename: Eriko
authors.initials: E
authors.lastname: Atsumi
authors.forename: Futoshi
authors.initials: F
authors.lastname: Higa
authors.forename: Kiyoko
authors.initials: K
authors.lastname: Tamai
authors.forename: Jiro
authors.initials: J
authors.lastname: Fujita
mesh_terms: D000328:Adult; D018450:Disease Progression; D006801:Humans; D008198:Lymph Nodes / Q000382:microbiology / Q000473:pathology*; D008297:Male; D008482:Mediastinum; D009162:Mycobacterium avium; D012189:Retrospective Studies; D014397:Tuberculosis, Pulmonary / Q000382:microbiology / Q000473:pathology*