A Pediatric Case of Malignant Melanoma Arising in an Mature Ovarian Cystic Teratoma Secondary to Malignant Transformation

Yoshimichi Yamaguchi, Yoshinobu Akasaka, Hiromi Hashimura
Department of Radiology, Kobe Children's Hospital

Abstract
Most common ovarian tumors in children are germ cell tumors.
When we see a tumor containing components of fat or bone, we can diagnose it as a mature teratoma.
However, if the mass mostly consists of solid components, it would be considered to be a mixed germ cell tumor, such as a teratoma complicated with yolk sac tumor or embryonal carcinoma.
　　In adult cases, a few reports can be seen of malignant transformation of an ovarian teratoma into squamous cell carcinoma or malignant melanoma.
　　We observed a case of a 12-year-old female who developed multiple metastases of malignant melanoma caused by malignant transformation of an ovarian teratoma.
　　When we see an ovarian teratoma mostly consisting of solid components and complicated with multiple metastases, even in children, we had better take into consideration the possibility of malignant transformation of the teratoma.

Keywords： Ovarian teratoma, Malignant transformation, Malignant melanoma, Child, MRI