Congenital osteolipoma of the skull.

A unique case of congenital osteolipoma of the skull occurred. A 27-year-old woman had multiple hard tumors affecting the frontal and parietal bones, the rim of the orbit, the maxilla, the base of the skull, and the horizontal part of the mandible on the right side. The slowly growing tumor was first noticed in the right parietal bone when she was born. The partially excised right frontoparietal lesion was composed of deformed and sclerotic trabeculae of bone and mature adipose tissue that formed an osteolipoma, which was regarded as hamartomatous. Its pathogenesis was suggested as associated with maldifferentiation of the mesenchyme or its derivatives toward the osseous and adipose tissue at the early development of the cranium.