NEUROFIBROMATOSIS of von Recklinghausen is characterized chiefly by tumor formation of peripheral nerves and pigmentary changes in the skin. Whether the neurofibromas originate from the fibrous connective tissue elements of the nerve sheath or from the sheath of Schwann, and hence whether the disorder involves chiefly mesodermal or ectodermal elements, has been the subject of controversy among pathologists. The condition is usually recognized by its cutaneous manifestations. These are (1) neurofibroma which may be sessile or pedunculated cutaneous lesions (fibroma molluscum of the older literature) or may be subcutaneous, and (2) areas of pigmentation (café-au-lait spots). The disease usually runs a benign course and is often noted as an incidental finding. However, the fact that 13 of our patients (21%) are dead or have undergone major surgical procedures as a result of lesions associated with von Recklinghausen's disease testifies to the seriousness of the condition in some patients. In 10