Ultrasonographic tissue characteristics of mushroom-shaped uveal melanoma

Purpose: To evaluate the ultrasonographic tissue characteristics of mushroom-shaped versus dome-shaped uveal melanoma and to compare them with the tumor vasculature. Methods: We examined clinically and ultrasonically 18 dome-shaped and 11 mushroom-shaped uveal melanomas (29 consecutive patients; mean age 57 years) and compared their normalized A-scan patterns. Using histological sections from a different set of patients (12 dome- and 17 mushroom-shaped tumors), we calculated the percentage of area covered by blood vessels. Results: A-scans of dome-shaped tumors presented low homogeneous reflectivity, whereas the heads of mushroom-shaped tumors had high arid irregular reflectivity (p < 0.001). The reflectivity of their bases was low and similar to dome-shaped tumors. The blood vessel area in the histological sections was significantly larger in the heads of mushroom-shaped tumors (0.88 ± 0.14%), compared both to their bases (0.29 ± 0.06%) (p < 0.001) and to dome-shaped tumors (0.07 ± 0.03%) (p < 0.0001). Conclusions: The ultrasonographic pattern suggests vascular congestion in the heads of mushroom-shaped tumors, probably due to strangulated blood vessels in the tumor neck.