Yolk Sac Tumor : Hepatoid
Yolk sac tumor (YST) of the testis shows a variety of architectural patterns that are admixed in varying proportions. Hepatoid pattern ( seen in 20% of cases): The tumor cells are polygonal and strongly resemble fetal hepatocytes. They have abundant eosinophilic cytoplasm and vesicular nuclei with prominent nucleoli. They are arranged in solid sheets, nests or trabeculae. They contain hyaline globules (as seen here) and are strongly positive for AFP and hepatocellular markers. Bile canaliculi-like structures are common; however, bile production is seen only rarely.