title: Subconjunctival mitomycin C before pterygium excision: an ultrastructural study.
abstract: OBJECTIVE
  Subconjunctival injection of mitomycin C (MMC) before pterygium excision is a new adjunctive therapy to decrease pterygium recurrence. This study aimed to investigate the ultrastructural changes in pterygium after subconjunctival injection of MMC.
  
  
  METHODS
  Four patients underwent subconjunctival injection of 0.1 mL of 0.15 mg/mL MMC 1 month before pterygium excision, and 2 patients served as controls without preoperative MMC injection. The excised specimens of pterygium were examined under transmission electron microscopy.
  
  
  RESULTS
  Epithelial cells of the treated pterygium remained unchanged. However, stromal fibroblasts were decreased in number, were oval rather than spindle-shaped, and had shrunken cytoplasmic processes; some were degenerating or apoptotic. Collagen and elastic fibers were decreased in density, disorganized, and degenerated. Capillary endothelial cells were thickened and swollen, with narrow or obliterated lumens. Axonal swelling and demyelination were observed.
  
  
  CONCLUSIONS
  Subconjunctival injection of MMC inhibits fibrovascular activity in the pterygial stroma, leading to degeneration of the extracellular matrix and nerve axons. These ultrastructural changes are consistent with the clinical observation of reduced vascularity in the pterygium after MMC injection and verify the effectiveness of subconjunctival MMC injection 1 month before pterygium excision in decreasing the risk of pterygium recurrence.
authors.affiliation: Department of Ophthalmology, College of Medicine, National Cheng Kung University, Tainan, Taiwan.
authors.forename: Yi-Sheng
authors.initials: YS
authors.lastname: Chang
authors.forename: Wen-Chung
authors.initials: WC
authors.lastname: Chen
authors.forename: Sung-Huei
authors.initials: SH
authors.lastname: Tseng
authors.forename: Chun-I
authors.initials: CI
authors.lastname: Sze
authors.forename: Chao-Liang
authors.initials: CL
authors.lastname: Wu
mesh_terms: D000368:Aged; D000477:Alkylating Agents / Q000008:administration & dosage*; D003228:Conjunctiva / Q000187:drug effects*; D004847:Epithelial Cells / Q000648:ultrastructure; D005260:Female; D005347:Fibroblasts / Q000648:ultrastructure; D006801:Humans; D007267:Injections; D008297:Male; D008875:Middle Aged; D016685:Mitomycin / Q000008:administration & dosage*; D011625:Pterygium / Q000473:pathology* / Q000601:surgery*; D017154:Stromal Cells / Q000648:ultrastructure
chemical_list: D000477:Alkylating Agents; D016685:Mitomycin