Histology of hepatoblastoma

(A) Hepatoblastoma is composed of fetal-type and embryonal-type cells, producing the characteristic "light and dark" pattern in hematoxylin and eosin-stained tissue sections.
(B) The fetal-type cells in the upper field (arrow) are lighter stained with granular cytoplasm while the embryonal cells in the lower field (arrowhead) are darker with hyperchromatic nuclei.
(C) Osteoid formation in hepatoblastoma (arrow).
(D) Gray cartilaginous stroma in hepatoblastoma (arrow).