Invited Review : The Origin of Mediastinal Germ Cell Tumors in Men

Mediastinal germ-cell tumors in men are generally thought to be primary at this site and to arise from extragonadal germ cells located in the thymus gland. Recent cytoge netic data have cast some doubt on this hypothesis and revived the alternative possibil ity of a testicular origin for these lesions. However, a review of the available evidence suggests that a primary mediastinal origin still remains the most likely explanation. The suggestion is made that the difficulties in identifying normal germ cells in the thymus gland may be due to their evolving into some type of somatic cell such as a myoid cell. Int J Surg Pathol 2(1):73-78, 1994