Lateral congenital dermal sinus tract associated with an intradiploic dermoid tumor. Case report.

This 20-month-old Negro baby boy was brought to a pediatric clinic 2 days after being struck in the right temporal region by a billiard ball. He was not rendered unconscious, but had gradually developed a large soft mass in that area. The child had been the product of a fullterm, uncompl'cated pregnancy. Shortly after birth the mother had noted a small "dimple" in the right temporal region; she did not seek medical advice and in the following months there had been no change in its character. Examina t ion . The physical examination was normal except for findings related to the presenting complaint. The soft tissue swelling in the right temporal region was firm and well circumscribed, erythematous, moderately tender, and measured 4 cm in its greatest diameter (Fig. 1 ). A small cutaneous defect was present over the dome of the lesion. It was hyperpigmented and fine hairs protruded from the oriface (Fig. 2 ) ; there was no drainage. A thorough neurological examination revealed no abnormality or midline malformation. Routine laboratory tests and an electroencephalogram were normal. Skull films revealed a solitary radiolucent area located in