Mirror-image solitary bone cyst of the humerus in a pair of mirror-image monozygotic twins

摘要

Mirror-image solitary bone cysts (SBCs) of the humerus in a pair of mirror-image monozygotic twins are presented. One twin was right-handed and had SBC at the left humerus. The other twin was left-handed and had SBC at the right humerus. The directions of the whirl of hair on their heads were opposite with each other. These findings strongly suggest cytogenetic factors in the aetiology or pathogenesis of SBC.