Malignant sacrococcygeal germ cell tumors in children in Taiwan: A retrospective single-center case series.

Although the incidence of malignant sacrococcygeal germ cell tumors (MSGCTs) is high in the East Asian countries, information about MSGCTs from this region is limited. This report aimed to analyze the data of children with MSGCTs in a single medical center in Taiwan.Patients aged 18 years or younger with primary MSGCTs or malignant recurrence of a sacrococcygeal teratoma who underwent surgery during the neonatal period between January 1999 and December 2016 were identified from the Linkou Chang Gung Cancer Center registry. The clinical features, laboratory data, and treatment outcomes were reviewed.Fifteen children (1 man and 15 women) with MSGCTs were identified. Sacrococcygeal tumors were present at birth in 7 patients. All patients presented with a bulging mass at the buttock region and they had normal alpha-fetoprotein levels at the time of diagnosis. They underwent primary excision of the tumor. Immature teratoma was histologically diagnosed in 5 neonates, and mature teratoma in 2. Only 1 patient with grade 3 immature teratoma received adjuvant chemotherapy. Two patients with mature teratoma developed malignant recurrence 1.6 and 2.1 years later, respectively. Eight patients were diagnosed with MSGCTs after the neonatal period. The common presenting symptoms included buttock asymmetry (37.5%), abdominal distension (25%), and constipation (12.5%). Seven patients had elevated alpha-fetoprotein levels for their age. They were administered neoadjuvant chemotherapy followed by tumor excision if a residual tumor was present. The histology of the excised tumor included mature teratoma (66.7%) and necrosis (33.3%). One patient with a normal alpha-fetoprotein level underwent primary tumor excision followed by adjuvant chemotherapy. Grade 2 immature teratoma with embryonal carcinoma was diagnosed histologically. Among the 15 patients with MSGCTs, 3 had a recurrence (at age of 2.1, 0.5, and 2.4 years, respectively) and 1 died (at age of 6.1 years) of disease progression. The 5-year overall and event-free survival rates were 90% and 80%, respectively.Children with MSGCTs had good overall prognoses in this case series. For those with sacrococcygeal mature teratoma or low-grade immature teratoma in the neonatal period, we recommend close follow-up for at least 3 years after surgery to detect malignant recurrence.