Ligamentum flavum hematoma in the lumbar spine.

A patient who presented with symptoms suggestive of nerve root compression secondary to an extradural mass was found to have a hematoma in the ligamentum flavum. Pathological examination of surgical specimens revealed an old hemorrhage, and hemosiderin deposits around organized granulation tissue within the ligamentum flavum. Vessels within the ligamentum flavum had, presumably, ruptured during minor trauma when the patient stood up.