Calcification in retinoblastoma.

Review of 40 cases of retinoblastoma revealed that histologic evidence of calcification was noted in 38 of the 40 tumors, whereas only three of 16 roentgenograms were positive for calcium. Calcificaton detected by roentgenograms and histopathologic examination correlated poorly with quantitative determination for tumor calcium. Compared to control eyes, however, eyes with retinoblastoma contain large amounts of calcium (1.2 vs. 218 mug/ml. ash). This calcification, though frequently not observed in standard roentgenograms, should be detected by the newer diagnostic modalities such as hypocycloidal polytomography, computerized transaxial tomography, ultrasonography, and radionuclide scintigraphy with technetium diphosphonate, a bone-scanning agent.