title: Calcium hydroxylapatite tissue filler discovered 6 years after implantation into the nasolabial fold: case report and review.
abstract: BACKGROUND
  Injectable calcium hydroxylapatite is becoming increasingly popular as a facial soft tissue filler, due in part to its purported longevity of esthetic correction compared with other materials, but little is known about its long-term histologic appearance and persistence in facial skin. We recently encountered calcium hydroxylapatite microspheres incidentally during Mohs surgery of the nasolabial fold 6 years after implantation.
  
  
  OBJECTIVE
  To describe the long-term histologic appearance of calcium hydroxylapatite microspheres in human facial skin and review the relevant literature with a consideration of clinical implications.
  
  
  METHODS
  Routine hematoxylin and eosin staining was performed on frozen and fixed excised tissue containing calcium hydroxylapatite microspheres. Additional fixed sections were stained using Movat's pentachrome method.
  
  
  RESULTS
  Numerous 4- to 20-mum round vacuoles were present throughout the reticular dermis associated with focal fibrosis, interstitial mucin, and little surrounding inflammation.
  
  
  CONCLUSIONS
  Calcium hydroxylapatite microspheres and associated fibrosis may persist in facial dermis at least 6 years after implantation, long after its clinical effects are thought to subside. Dermatologists and dermatopathologists must be mindful of dermal implants because it is likely that incidental encounters will be an increasingly common occurrence.
authors.affiliation: Mohs/Dermatologic Surgery Division, Scripps Clinic La Jolla, California 92037, USA.
authors.forename: Peter R
authors.initials: PR
authors.lastname: Shumaker
authors.forename: E Lawrence
authors.initials: EL
authors.lastname: Sakas
authors.forename: Michael H
authors.initials: MH
authors.lastname: Swann
authors.forename: Hubert T
authors.initials: HT
authors.lastname: Greenway
mesh_terms: D001672:Biocompatible Materials / Q000008:administration & dosage*; D002280:Basal Cell Carcinoma / Q000473:pathology / Q000601:surgery; D003357:Cosmetic Techniques; D020405:Dermis / Q000473:pathology*; D017886:Durapatite / Q000008:administration & dosage*; D005260:Female; D005355:Fibrosis; D005549:Foreign-Body Reaction / Q000473:pathology*; D006801:Humans; D007271:Injections, Intradermal; D008863:Microspheres; D008875:Middle Aged; D015580:Mohs Surgery; D019736:Prostheses and Implants; D012878:Skin Neoplasms / Q000473:pathology / Q000601:surgery; D013997:Time Factors
chemical_list: D001672:Biocompatible Materials; D017886:Durapatite