Impact of the histological type on the prognosis of patients with prenatally diagnosed sacrococcygeal teratomas: The results of a nationwide Japanese survey

Purpose: To identify the impact of the histological diagnosis on the prognosis of prenatally diagnosed sacrococcygeal teratoma (SCT), we analyzed the data obtained during prenatal surveillance and assessed the postnatal outcomes in a large cohort of fetuses with SCT in Japan. Methods: A nationwide retrospective cohort study was conducted among 97 fetuses prenatally diagnosed with SCT between 2000 and 2009. Of these, 84 had a histological diagnosis. In addition, we conducted a second surveillance program of the prognosis of 72 patients who were reported to be alive at the initial surveillance conducted 2 years previously. Results: The tumors comprised 51 (61 %) mature teratomas, 33 (39 %) immature teratomas and 0 (0 %) malignant teratomas. Immature teratomas were also associated with a significantly higher mortality rate (immature teratomas: 8/31, mature teratomas: 2/48). Late recurrence was observed in six of 72 cases (8.3 %). Among these six cases, recurrence with a malignant component was observed in four patients. All six patients were successfully treated. Conclusions: Mature teratoma was the most common histological type observed in this study. The patients with immature teratomas exhibited an increased risk of mortality. Late recurrence was observed in 8.3 % of the cases.