Figure 2.

Histopathological findings (B–F: hematoxylin and eosin (HE) method). (A) The resected specimen contained a well-demarcated yellowish tumor with massive central necrosis, encompassing 80% of the tumor mass. (B) Papillary growth shows a dual population of cuboidal surface cells overlaying stromal round cells. (C) Each tumor cell was uniform, round or polygonal, with round bland nuclei having no nucleoli and a fine chromatin. The cytoplasm was eosinophilic, and nuclear fission was scarcely observed. (B, D–F) The tumor proliferated with various growth patterns such as (B) papillary, (D) solid, (E) sclerotic and (F) hemorrhagic.