Infantile myofibromatosis is a distinct clinicalpathologic entity occurring primarily in neonates and infants either as a single nodular lesion or as a multicentric form. We have recently studied two cases of this disorder in neonates, and a third involving the father of one of these infants, all documented by biopsy. Evidence in support of an autosomal-dominant mode of inheritance for infantile myofibromatosis and of its potential to recur after a long period of quiescence is presented.