Chordoma is an age-dependent bone cancer that is rare in children. Reports of chordoma in children with TSC, an autosomal dominant neurocutaneous syndrome, suggest a biological relationship between the two diseases.  We compared 10 children reported with TSC and chordoma to 65 pediatric chordoma cases reported to 17 US population-based cancer registries in SEER. The TSC-associated chordomas had a much younger median age at diagnosis overall, as well as a different proportion and median age at diagnosis of sacral tumors than the pediatric chordomas in SEER. Also, patients with TSC-associated sacral chordoma had longer tumor-free survival than pediatric sacral chordoma patients in SEER. Future clinical and molecular studies documenting the joint occurrence of these two diseases may reveal the biological basis for their association. (By Dr. Dilys M. Parry, http://jmg.bmj.com/content/early/2011/01/24/jmg.2010.085092?papetoc)