Thickened calvaria, exostosis of the frontal bone, and increased density of the cranium occur in most cases. Large single digit may occur. New bone formation may occur on the long bones.
Hypomelanotic macules are the first manifestations.
Intracranial calcifications occur in about one third of cases and generally involve the cerebrum and, less commonly, the cerebral cortex. Increased intracranial pressure brought about by the growing tumors may cause obstruction of the cerebral fluid circulation and separation of the cranial sutures. Pressure exerted by tumors is associated with epileptic seizures, schizophrenia, and autism. Honeycomb lung occur most commonly in adult females. Polycystic kidneys and angiomyolipoma of the kidneys are frequent.