Retinoblastoma. CT diagnosis.

Computed tomography (CT) scan is a valuable adjunct in the differential diagnosis and management of retinoblastoma. Thirty-one of 33 retinoblastoma patients studied with high resolution computed tomography had intraocular calcification demonstrable in at least one eye. Over 80% of tumors showed evidence of calcification on CT scan. The degree of calcification appeared to depend upon tumor size; only small tumors were devoid of calcification. The amount and distribution of calcification was similar on both histological and CT review. In patients under three years of age in whom a retinoblastoma is suspected, the presence of calcification on CT scan is virtually diagnostic of retinoblastoma; patients with leukocoria without calcification on CT probably have a simulating lesion.