Which pathologic characteristics influence echographic patterns of retinoblastoma?

Disagreement still exists regarding the influence of rosette formation, pseudorosettes, necrotic changes, vascularity, and calcification on the echographic characteristics of retinoblastoma. To further evaluate the echographic pattern of retinoblastoma confirmed by tissue diagnosis, we studied 11 consecutive cases of retinoblastoma and correlated pathologic findings with A- and B-scan echographic findings. In five patients with heavily calcified tumors, the A-scan echograms were more accurate in documenting reflectivity and revealed an extremely highly reflective pattern attenuating the ultrasonic beam substantially and casting characteristic shadows on the sclera. The B-scan echogram revealed a mass attenuating the ultrasound beam. This mass had dense focal echoes persisting at lower sensitivity within the tumor. In five patients with mild calcification on pathological examination, the A-scan echogram showed a highly reflective pattern. In one case with no calcification, the A-scan echogram revealed a medium reflective pattern. The B-scan echogram revealed a well-defined mass in each case. The degree of rosette differentiation, pseudorosettes, or necrosis failed to correlate with A-scan echographic pattern specific for retinoblastoma. No case showed a cystic appearance on B-scan echogram regardless of the degree of necrosis seen in the pathologic specimen. The echographic findings in retinoblastoma depend primarily on the degree of calcification and are not influenced independently by other specific pathologic characteristics of the tumors.