Aneurysmal bone cyst--simple bone cyst, two aspects of the same pathologic entity?

An unusual case of aneurysmal bone cyst recurring after operation as a simple bone cyst is reported. Different theories on etiology and pathogenesis of aneurysmal bone cyst, simple bone cyst, and central giant cell granuloma of the jaws are resumed and similarities demonstrated. It is suggested that these three lesions have a common dysvascular etiology and that local environmental factors within the bone may differentiate the pathogenesis.