The term "infantile myofibromatosis" was coined in 1981 to describe a rare type of soft-tissue tumor in infants. Solitary lesions are usual, but extremely rare in the skull. An infantile case involving a lesion in the left parietal bone is described. The patient was a 6-month-old girl admitted with a mass measuring 2 x 2 cm in the left parietal region. Skull x-rays showed an osteolytic lesion with a sclerotic margin in the parietal bone. Computed tomographic (CT) scans revealed a low-density mass with homogeneous enhancement. The tumor adhered to the dura and had destroyed the left parietal bone. Histological examination disclosed spindle-shaped cells arranged in short bundles and abundant vasculature. Phosphotungstic acid hematoxylin staining revealed longitudinal fibrils resembling myofibroblasts. This is the first report in which CT findings are described in a case of infantile myofibromatosis with a solitary lesion occurring in the skull.