title: [Analysis of 602 cases of nevus of Ota and study of ultrastructures on the melanocytes].
abstract: OBJECTIVE
  To analyze clinical information and efficacy of 602 cases of nevus of Ota, and investigate the histopathology and ultrastructure on the melanocytes before and after Q-switched Alexandrite laser irradiation.
  
  
  METHODS
  Clinical information of 602 cases of nevus of Ota were collected by applying clinical records, checking photos, and inquiry to patients by letters and telephones. Ten cases of biopsies were observed by light microscopy and 6 cases by electron microscopy before and after laser irradiation.
  
  
  RESULTS
  Nevus of Ota included congenital and acquired cases. Skin lesions mainly occurred in adolescence for the acquired cases. The main colours of lesions were brown and blue. The most local lesions were zygomata, temporal regions, and lower eyelids. According to multiple regression, the more treatment times, the better results. The effective rate was 85.20% and 100% after 6 and 9 treatment times, respectively, while the cure rate was 55.72% and 98.46%, respectively. The eyelids involved and Tanino types influenced the treatment times by COX models analysis. Electron microscopy showed many melanosomes in the dermal melanocytes. After laser irradiation, the outlines of the dermal melanocytes were observed, the melanosomes were broken to dense and tiny granules.
  
  
  CONCLUSIONS
  Q-switched Alexandrite laser is safe and effective for the treatment of nevus of Ota. The results of treatment are correlated with the area and size of the lesion. The dermal melanocytes in nevus of Ota can be selectively destroyed by Q-switched Alexandrite laser with less injury around tissues.
authors.affiliation: Department of Dermatology, PUMC Hospital, CAMS and PUMC, Beijing 100730, China.
authors.forename: Hong-wei
authors.initials: HW
authors.lastname: Wang
authors.forename: Jia-bi
authors.initials: JB
authors.lastname: Wang
authors.forename: Yue-hua
authors.initials: YH
authors.lastname: Liu
authors.forename: Kai
authors.initials: K
authors.lastname: Fang
authors.forename: Guo-tiao
authors.initials: GT
authors.lastname: Jiang
authors.forename: Ya-gang
authors.initials: YG
authors.lastname: Zuo
mesh_terms: D000293:Adolescent; D000328:Adult; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D053685:Laser Therapy; D008297:Male; D008544:Melanocytes / Q000648:ultrastructure*; D020460:Melanosomes / Q000528:radiation effects / Q000648:ultrastructure; D009507:Nevus of Ota / Q000532:radiotherapy* / Q000648:ultrastructure; D012867:Skin / Q000648:ultrastructure; D012878:Skin Neoplasms / Q000532:radiotherapy* / Q000648:ultrastructure