Rapid growth of a mature mediastinal teratoma in a middle-aged woman: A case report.

A mediastinal mass was incidentally detected in a 42-year-old Japanese woman during a routine medical checkup. Computed tomography revealed a 7-cm, well-circumscribed multilocular cystic mass consistent with a mature cystic teratoma; however, no solid or cystic lesion had been detected at a voluntary complete medical checkup 1.5 years earlier. An anterior mediastinal tumor resection was performed, and the histopathological findings were compatible those of a mature teratoma. Although the mechanisms that underlie rapid growth of all tridermic components in a mature teratoma remain unclear, it is presumed that the mechanisms involve hemorrhage, rupture, inflammation caused by pancreatic enzymes, and estrogen hormone activity. We presented a rare case of a rapid formation of a mediastinal teratoma, which revealed that a mediastinal teratoma with all tridermic components could develop in a relatively short period.