title: Mycobacterium kansasii infection diagnosed by pleural fluid cytology: a case report.
abstract: BACKGROUND
  Identification of disseminated nontuberculous Mycobacterium infection is a challenge, especially when it occurs in patients without a known cause of immunosuppression. Acid-fast organisms in the pleural fluid are rare and easily missed, especially when they occur in patients without a clinical suspicion of infection. The classical cytologic picture of tuberculous pleural fluid with lymphocytosis and paucity of mesothelial cells is not seen.
  
  
  METHODS
  A 57-year-old man presented with chronic neutrophilia of unknown etiology together with chest pain and bilateral pleural effusions. Pleural fluid cytology revealed organisms seen in the cytoplasm of numerous macrophages and neutrophils, creating a "negative image" on Diff-Quik smears. Acid-fast stains demonstrated intracellular acid-fast bacilli consistent with mycobacteria. Microbiologic studies with DNA probe technology resulted in identification of the mycobacterial organism as Mycobacterium kansasii.
  
  
  CONCLUSIONS
  Nontuberculous Mycobacterium should be included in the differential diagnosis in patients with inflammatory, exudative pleural effusions.
authors: Department of Pathology, University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania, and University of Alabama, Birmingham, Alabama 15213, USA.
authors: Akosua B
authors: AB
authors: Domfeh
authors: Laurentia
authors: L
authors: Nodit
authors: Joel F
authors: JF
authors: Gradowski
authors: Sheldon
authors: S
authors: Bastacky
mesh_terms: D006099:Granuloma / Q000473:pathology; D006801:Humans; D008198:Lymph Nodes / Q000473:pathology; D008264:Macrophages / Q000382:microbiology; D008297:Male; D008875:Middle Aged; D009165:Mycobacterium Infections, Nontuberculous / Q000175:diagnosis*; D019909:Mycobacterium kansasii / Q000166:cytology / Q000302:isolation & purification*; D009504:Neutrophils / Q000382:microbiology; D010994:Pleura / Q000382:microbiology*