title: Restylane persistent for 23 months found during Mohs micrographic surgery: a source of confusion with hyaluronic acid surrounding basal cell carcinoma.
abstract: BACKGROUND
  Restylane (Q-Med, Uppsala, Sweden), a hyaluronic acid (HA) that is microbiologically produced and then cross-linked, is becoming popular as a dermal filler for improvement of facial lines and wrinkles. However, it is currently believed that the clinical and histologic persistence of this filler is from 6 to 9 months. We recently encountered Restylane in tissue where it had been implanted 23 months prior to removal of a basal cell carcinoma (BCC) on the lip, and its presence caused some confusion with HA that surrounds BCC nests.
  
  
  OBJECTIVE
  To show and to contrast the histologic dermal appearance of Restylane and its metachromatic staining characteristics with toluidine blue from those of HA that surrounds BCC nests.
  
  
  METHODS
  Toluidine blue staining at pH 7.07 was performed on excised tissue containing Restylane and BCC on the upper lip.
  
  
  RESULTS
  Restylane appeared as reddish-purple amorphous masses, whereas the HA that frames BCC nests appeared redder and more well defined.
  
  
  CONCLUSIONS
  The amorphous metachromatic reddish-purple color staining of Restylane with toluidine blue is due to its HA content. This staining pattern should be differentiated from the well-defined red color of HA that normally borders BCC nests. Restylane may persist in the dermis as long as 23 months after implantation.
authors.affiliation: Bennett Surgery Center Inc., 1301 20th Street, Suite 570, Santa Monica, CA 90404, USA. drrgb@ucla.edu
authors.forename: Richard
authors.initials: R
authors.lastname: Bennett
authors.forename: Muba
authors.initials: M
authors.lastname: Taher
mesh_terms: D000276:Adjuvants, Immunologic / Q000032:analysis; D002280:Basal Cell Carcinoma / Q000737:chemistry / Q000473:pathology / Q000601:surgery; D004396:Coloring Agents; D003357:Cosmetic Techniques; D005260:Female; D005629:Frozen Sections; D006801:Humans; D006820:Hyaluronic Acid / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000032:analysis; D008046:Lip; D008875:Middle Aged; D015580:Mohs Surgery; D012878:Skin Neoplasms / Q000737:chemistry / Q000473:pathology / Q000601:surgery; D013194:Staining and Labeling; D014048:Tolonium Chloride
chemical_list: D000276:Adjuvants, Immunologic; D004396:Coloring Agents; D014048:Tolonium Chloride; D006820:Hyaluronic Acid; C445361:Restylane