title: Late unilateral hematoma after breast augmentation.
abstract: BACKGROUND
  Late hematoma after breast augmentation is a rare phenomenon with unproven etiology.
  
  
  METHODS
  Five patients presented with a late unilateral hematoma after receiving bilateral, submuscular, smooth, round, silicone gel implants for cosmetic breast augmentation. All patients underwent explantation and capsulectomy. Extensive clinical and histological analysis of all capsules was performed.
  
  
  RESULTS
  All patients presented with progressive unilateral breast enlargement with at least a doubling of their breast size. Breast enlargement developed nine, 12, 14, 22 and 38 years, respectively, after initial implant insertion and in the absence of any known trauma. Patients presented for treatment one, three, four, nine and 12 months, respectively, after initially noticing breast enlargement. This enabled a sequential analysis of the events occurring on the surface of the capsule and within the structure of the capsule. Macroscopic and microscopic analysis of all capsules demonstrated multiple areas of recent and older hemorrhage, both within the structure of capsules and on the surface of the capsule. Continuing recurrent bouts of acute hemorrhage were observed even nine and 12 months after initial hematoma development. The position of medium-size vessels within the capsules corresponded to the sites of recurrent bleeding within capsules.
  
  
  CONCLUSIONS
  Late hematomas presented from nine to 38 years after submuscular breast augmentation with a doubling of breast size. Late hematomas appeared to result from multiple recurrent bouts of bleeding within the structure of the capsules. This leads to recurrent bleeding on the surface of the capsules. Breast enlargement develops progressively over time rather than acutely. Continuing acute hemorrhage persisted up to one year after initial hematoma development. This progression suggests a process analogous to a chronic expanding hematoma that has been described in other areas of the body. Failure to remove a capsule could result in long-term continuing bleeding from vessels within the capsule.
authors.affiliation: Division of Plastic Surgery, and the University of Toronto, Toronto, Ontario.
authors.forename: Walter
authors.initials: W
authors.lastname: Peters
authors.affiliation: Department of Anatomic Pathology and Cytology, St Michael's Hospital, and the University of Toronto, Toronto, Ontario.
authors.forename: Victor
authors.initials: V
authors.lastname: Fornasier
authors.affiliation: Department of Pathology and Laboratory Medicine, Mount Sinai Hospital, and the University of Toronto, Toronto, Ontario.
authors.forename: David
authors.initials: D
authors.lastname: Howarth
keywords: Breast implants; Complications; Late hematoma