Osteosarcoma as a primary second tumor in a patient with nonhereditary retinoblastoma

A case of osteosarcoma of the distal femur 13 years after the occurrence of a unilateral nonhereditary retinoblastoma is reported. The karyotype of circulating lymphocytis was found to be normal. The existence of a linkage between the two neoplasms due to a subtle chromosomal abnormality is discussed.