Progressive spontaneous unilateral enlargement of the breast twenty-two years after prosthetic breast augmentation.

Late spontaneous enlargement of the breast is a rare complication after prosthetic breast augmentation. It has been intermittently described in the literature over the last 24 years but its exact aetiology remains unknown. Several possible aetiologies have been proposed. We present a case of a 46-year-old female who developed spontaneous asymmetrical breast enlargement 22 years post-bilateral breast augmentation without any known precipitating factors. Radiographic imaging revealed a periprosthetic collection occupying 70% of the volume inside the capsule. Initial recommendations for capsulectomy and removal of the breast implant were delayed for a year by the patient who subsequently represented with ongoing enlargement of the affected breast. Pathological findings revealed an intact silicone implant surrounded by laminated blood clot, similar in appearance to a chronic subdural haematoma. The literature is reviewed and the possible pathophysiological mechanisms of this unusual condition discussed.