Fig. 2

Histology of tumors in cystic (a and b) and solid (c and d) lesions. Monomorphic cells with round-to-oval nuclei and a pale cytoplasm and lacework of the basement membrane material were detected (a, x50; b, x150). In contrast, the tumor in the solid lesion was composed of cells with mild-to-moderate nuclear atypia and eosinophilic cytoplasm surrounded by vessels with a hemangiopericytomatous growth pattern (c, x50; d, x150)