Yolk Sac Tumor : Endodermal Sinus Pattern
Yolk sac tumor (YST) shows a variety of architectural patterns that are admixed in varying proportions. Endodermal sinus (perivascular) pattern: This pattern displays a papillary structure called Schiller-Duval body. It consists of a fibrovascular core with a single central thin-walled vessel in a hyalinized stroma surrounded by a one or more layers of cuboidal tumor cells with clear cytoplasm. The papillary structure is contained within a cystic space lined by flattened cells. Schiller-Duval body is a hallmark of YST but is not required for diagnosis. Tangential sections through these structures can result in fibrovascular cores of tissue surrounded by a complex pattern of anastomosing extracellular spaces lined by malignant cells.