Germ cell tumor-like neoplasms occurring outside the anatomic midline.

Most germ cell tumors occur in the gonads or in extragonadal sites in the anatomic midline; this article reviews tumors with similar or identical histologic features that arise in other topographic locations. Such lesions often represent the presence of "germ cell-like" or "germinal" components in what is otherwise recognized as a somatic neoplasm; however, they may also occur in pure form. The morphologic and immunohistochemical features of these proliferations are reviewed, according to the types of germ cell tumors that they recapitulate.