title: [Pathological study of mycobacterium abscessus keratitis].
abstract: OBJECTIVE
  To characterize the cytopathology, histopathology, immunohistochemistry and ultrastructural organization features of Mycobacterium abscessus keratitis.
  
  
  METHODS
  This retrospective case report included six cases with the lesions tissues scraped from acute phase of mycobacterium abscessus keratitis after corneal foreign body removal. Among the 6 scrapings, 4 were tested for Ziehl-Neelsen acid-fast staining and 3 were examined by transmission electron microscopy (TEM). The corneal tissues of 2 cases in chronic phase of the disease were collected during keratoplasty and were examined by pathological examination including hematoxylin-eosin (HE) staining, acid-fast staining, immunohistostaining and TEM.
  
  
  RESULTS
  A single or fascicular red bacilli were observed after acid-fast staining in the four cases of corneal scrapings. The smear samples contained a large number of neutrophils and necrotic corneal epithelium and stroma tissue accompanying with a large number of mycobacteria that were positive for acid-fast staining scattered in and out of inflammatory cells. The corneal buttons obtained at keratoplasty in the 2 patients demonstrated corneal epithelial hyperplasia, stroma degeneration, necrosis and exelcosis, neutrophil and lymphocyte infiltration, neovascularization and fibrous hyperplasia, but no positive mycobacteria by Ziehl-Neelsen acid-fast staining. There were no CD4(+) or CD8(+) cells from immunohistochemistry examination. TEM of the corneal scrapings of the 3 cases showed phagocytosis of mycobacterium abscessus in mononuclear macrophage or neutrophils, inclusion compounds of small vacuoles and metachromatic granules in the thallium. TEM of corneal buttons of 2 cases showed slender rod-shaped mycobacteria with several to dozens of finely ground particles with high electron-dense, but no cell wall (L-form) or inclusion compounds.
  
  
  CONCLUSIONS
  Mycobacterium abscessus keratitis presents acute purulent inflammatory changes in early stage and advances to chronic and non-specificity inflammation changes in late stage. L-formed mycobacterium abscessus make the disease protraction.
authors.affiliation: Department of Ophthalmology, Wuxi People's Hospital, Wuxi 214023, China.
authors.forename: Li
authors.initials: L
authors.lastname: Yin
authors.forename: Yong
authors.initials: Y
authors.lastname: Yao
authors.forename: Huai-jin
authors.initials: HJ
authors.lastname: Guan
authors.forename: Jun-fang
authors.initials: JF
authors.lastname: Zhang
authors.forename: Hai-hong
authors.initials: HH
authors.lastname: Shi
authors.forename: Ling
authors.initials: L
authors.lastname: Yang
mesh_terms: D000328:Adult; D003315:Cornea / Q000473:pathology; D006801:Humans; D007634:Keratitis / Q000382:microbiology* / Q000473:pathology*; D008297:Male; D008875:Middle Aged; D009161:Mycobacterium / Q000302:isolation & purification*; D009164:Mycobacterium Infections / Q000473:pathology*; D012189:Retrospective Studies