c-KIT codon 816 mutation in a recurrent and metastatic dysgerminoma of a 14-year-old girl: case study.

Dysgerminomas are rare female germ-cell tumors that correspond histologically and immunohistochemically to seminomas. Analogous to seminomas, most dysgerminomas respond very well to cisplatin- or carboplatin-based chemotherapy and to radiotherapy. KIT tyrosine kinase is crucial for normal germ-cell development, and its expression is observed in the majority of seminomas and dysgerminomas. Recently, activating KIT mutations were described in a panel of male germ-cell tumors [5, 10]. All mutations were localized in exon 17, encoding the second tyrosine kinase domain. Because receptor tyrosine kinase KIT might also be involved in the pathogenesis of dysgerminomas, we studied the expression and mutational status of a pure dysgerminoma, which was sent to our department for diagnostic reasons. The tumor revealed an exon 17 D816 V mutation in the c-KIT gene and strong KIT expression was found immunohistochemically. Clinically, the tumor was highly aggressive and resistant to carboplatin-based chemotherapy. Our case raises the question of whether exon 17 c-KIT mutations might be involved in the pathogenesis of dysgerminoma and whether exon 17 KIT mutations may predict aggressive and chemotherapy-resistant behavior of dysgerminomas.