title: Migrating granulomatous chronic reaction from hyaluronic acid skin filler (Restylane): review and histopathological study with histochemical stainings.
abstract: BACKGROUND
  A unique case is presented in whom an allergic reaction to Restylane filler, associated with migrating granulomas, persisted despite medical interventions. A histopathological study was requested for evidence at court.
  
  
  METHODS
  Hematoxylin-eosin, alcian blue and colloidal iron staining were applied to skin sample biopsies obtained 5 months and 3 years after the hyaluronic acid (HA) injection.
  
  
  RESULTS
  The histological staining highlighted the presence of the filler inside the foreign body granuloma and in the derma of a biopsy obtained after 5 months; a small amount of filler was discovered within a granulomatous reaction 3 years after the injection.
  
  
  CONCLUSIONS
  Smaller fragments of HA display inflammatory, angiogenic and immune-stimulatory activities. Intradermal skin testing before the start of HA filler therapy, and before each subsequent injection, may prevent legal implications for the plastic surgeon. Informed consent to skin tests should be obtained.
authors.affiliation: Department of Anatomy, Histology, Legal Medicine and Orthopedics, Sapienza University, Rome, Italy.
authors.forename: Rossana
authors.initials: R
authors.lastname: Cecchi
authors.forename: Andrea
authors.initials: A
authors.lastname: Spota
authors.forename: Paola
authors.initials: P
authors.lastname: Frati
authors.forename: Barbara
authors.initials: B
authors.lastname: Muciaccia
mesh_terms: D003879:Dermatologic Agents / Q000009:adverse effects*; D020405:Dermis / Q000473:pathology; D005148:Facial Dermatoses / Q000139:chemically induced / Q000473:pathology*; D005260:Female; D006105:Granulomatous Disease, Chronic / Q000139:chemically induced / Q000473:pathology*; D006801:Humans; D006820:Hyaluronic Acid / Q000009:adverse effects / Q000031:analogs & derivatives*; D008875:Middle Aged; D012883:Skin Ulcer / Q000139:chemically induced / Q000473:pathology*; D013194:Staining and Labeling; D050151:Subcutaneous Fat / Q000473:pathology
chemical_list: D003879:Dermatologic Agents; D006820:Hyaluronic Acid; C445361:Restylane