BONE-TUMORS OTHER THAN OSTEOSARCOMA AFTER RETINOBLASTOMA

Background. The most frequent second malignant neoplasm after retinoblastoma is osteosarcoma, which may be associated with radiation therapy or arise de novo in patients with bilateral retinoblastoma. Methods. Clinical, pathologic, and diagnostic imaging findings in two patients with Ewing sarcoma (ES) and one with peripheral neuroepithelioma (PN) are presented. Results. Second malignant neoplasms located in the extremities or pelvis were seen 12-18 years after initial diagnosis of unilateral (two patients) or bilateral (one patient) retinoblastoma. The patients with unilateral retinoblastoma were treated by enucleation only; the other received ocular radiation therapy and chemotherapy. To the knowledge of the authors, this is the first documentation of round blue cell tumor after unilateral retinoblastoma. Conclusions. ES and PN should be included in the differential diagnosis of malignant neoplasms occurring after treatment of unilateral or bilateral retinoblastoma.