Infantile hemangioma in four siblings.

Infantile hemangioma is the most common tumor of infancy, affecting approximately 5.0% of Caucasians. We present the unlikely occurrence of four siblings with infantile hemangiomas; there was no family history of the tumor. One child was low birth weight, there was one set of twins, and three infants had multiple lesions. The estimated probability of four consecutive children having this phenotypic expression of infantile hemangioma is 1/4,232,804.