B-scan ultrasonography in the diagnosis of atypical retinoblastomas.

Contact B- scan ultrasonography (Bronson-Turner unit) was performed on fourteen patients with retinoblastoma. In ten cases, the patient presented with leukocoria, and ultrasonography was helpful in confirming the clinical diagnosis. In four atypical cases contact B-scan ultrasonography was instrumental in making the diagnosis. The ultrasonographic pattern for retinoblastoma is characteristic but not pathognomic. There is a solid intraocular echo corresponding to the tumor and within it are numerous dense focal echoes which persist at lower sensitivities, suggesting calcification. Calcification was demonstrated ultrasonographically and confirmed histologically in all four of these atypical cases, but routine skull x-rays failed to demonstrate calcium in three of the four children. Contact B- scan ultrasonography is a safe and simple procedure which may provide valuable diagnostic information in children with suspected retinoblastoma.