Background: Immature ovarian teratoma is the third most common germ cell tumor (GCT) following dysgerminoma and endodermal sinus tumor. The treatment of choice during childbearing age for immature teratoma composes of unilateral oophorectomy and in case of metastatic disease postoperative chemotherapy (BEP). Finding a solid mass in the peritoneal or chest cavity during routine follow up raises the suspicion of distance recurrence. DiSaia was the first to describe the appearance of benign distant metastasis during routine follow up. He termed this phenomenon "chemotherapeutic retroconversion". Latter, Logothetis described what seems to be a similar phenomenon in testicular non-seminomatous germ cell tumor (NSGCT) that he called the "growing teratoma syndrome".
Case: We present a case of a 12-year-old girl treated for growing teratoma syndrome after primary ovarian GCT.
Conclusion: Review of the literature shows that this syndrome and the "chemotherapeutic retroconversion" are probably the same phenomenon.