Excretion of vanilmandelic acid in the urine of retinoblastoma patients.

The idea of determining the urinary excretion of vanilmandelic acid (VMA) in children with retinoblastoma derives from the fact that elevated amounts of VMA were found in children with neurogenic tumours and especially neuroblastoma. The method of VMA analysis and the results are discussed. In view of the fact that in only 5 out of our 12 patients an elevated urinary VMA excretion was found, we cannot recommend this determination as a routine diagnostic procedure. However, further research in this direction is necessary.