Background: Patients who survive retinoblastoma (RB) are at risk for having second nonocular tumors, usually osteosarcomas, which often are fatal. Such patients almost always have bilateral RB.
Methods: This article reports a woman who, at the age of 1 year had been cured of a unilateral RB by radiation therapy and enucleation. Eighteen years later, she had a sinonasal small cell tumor that rapidly recurred and proved fatal 2 months after surgical debulking. The tumor was studied by immunohistochemistry and electron microscopic (EM) examination.
Results: It showed diffuse neuron-specific enolase staining, focal weak staining for chromogranin, synaptophysin, and Leu-7 monoclonal antibodies in paraffin-embedded, B5-fixed tissue (Great Lakes Diagnostics, Troy, MI). EM study showed an undifferentiated primitive neuroectodermal tumor with many polyribosomes, simple cell junctions, few microtubules, and rare dense core granules.
Conclusions: The combined immunohistochemical, ultrastructural, and clinical features of the tumor were interpreted as a sinonasal primitive neuroectodermal tumor with early neuronal differentiation. The tumor was pathologically indistinguishable from poorly differentiated olfactory neuroblastoma (ONB) and Ewing sarcoma.