Multifocal osteosarcoma following retinoblastoma.

Three survivors of retinoblastoma, one with hereditary bilateral and two with nonhereditary (spontaneous) unilateral disease, developed multifocal osteosarcoma. For one patient, unilateral retinoblastoma was followed by primitive neuroepithelioma at age 13 years. Multifocal chondroblastic osteosarcoma represented the patient's third malignant neoplasm. The course of multifocal osteosarcoma in these three patients compares to that of multifocal osteosarcoma which presents de novo in other patients without prior retinoblastoma.