Neurofibrosarcoma as a complication of von Recklinghausen neurofibromatosis.

Neurofibrosarcoma (NFS), which is rare in the general population, occurs with excessive frequency among patients with von Recklinghausen neurofibromatosis (NF-1). Among 693 patients with NF-1 enrolled in the Baylor NF Program, 24 patients (3.5%) developed NFS or one of its variant forms. Nine of the twenty-four patients developed NFS within 3-94 months after enrolling in the Program for other reasons. Focus on these 9 patients alone suggests that the relative risk for patients with NF-1 developing NFS is 10-10,000 times greater than for the general population. Also, in NFS cohorts, patients with NF-1 are almost twice as likely to be under 30 years of age.