Challenges in Managing Primary Retroperitoneal Germ Cell Tumors in Children: The Role of Neoadjuvant Chemotherapy

Primary retroperitoneal germ cell tumors (GCTs) are rare and often present as large masses with close anatomical relationships to adjacent organs and vessels, which can complicate surgical management. Indications for neoadjuvant chemotherapy are guided by pathological features and serum alpha-fetoprotein (AFP) levels; however, these levels may be difficult to interpret in infants. While some tumors respond to neoadjuvant chemotherapy, others may progress during treatment, making surgical resection even more challenging. This study aimed to evaluate the management and outcomes of retroperitoneal GCTs within a national multicenter cohort.

This national retrospective study included pediatric patients with primary retroperitoneal GCTs who underwent surgical resection between 2000 and 2022. Data were identified through the French Very Rare Tumors Committee (FRACTURE) database, the TGM-2013 study, and the Groupe des Chirurgiens Pédiatres Opérant des Tumeurs (GCPOT) collaborative group.

A total of 24 children were included (17 girls). The median age and weight at diagnosis were 5.2 months (range 1.6-44 months) and 7.4 kg (range 4-14 kg), respectively. Five patients (29%) had a prenatal diagnosis. The median tumor volume was 563 cm³ (range 280-986 cm³), and 17 patients (71%) initially presented with vascular risk factors. AFP levels were elevated for age in eight patients (33%), including four infants under 1 year old, with a median level of 7500 ng/mL (range 1775-70,860 ng/mL). Eight patients (33%) received neoadjuvant chemotherapy, six of whom had age-elevated AFP. Following chemotherapy, tumor volume decreased in three cases, while five patients experienced tumor progression. Complete (R0) resection was achieved in 18 cases (75%). Histological analysis revealed 11 mature teratomas (46.0%), 9 immature teratomas (37.5%)-including 5 grade 1, 2 grade 2, and 2 grade 3-and 4 malignant GCTs with a yolk sac tumor (YST) component (16.5%). One patient with perioperative tumor capsular rupture and metastatic YST received adjuvant chemotherapy. Major complications (Clavien-Dindo ≥ 3) occurred in five cases (21%). Two deaths were recorded: one postoperatively due to mesenteric ischemia and one due to local and metastatic YST progression. After a median follow-up of 7.1 years (range 2.7-12.3 years), 22 patients (91.6%) are alive with no evidence of recurrence.

This study confirms the favorable oncological prognosis of primary retroperitoneal GCTs in children. Neoadjuvant chemotherapy should be approached with caution, as its impact on tumor volume may be limited. Furthermore, it carries a potential risk of growing teratoma syndrome, which can ultimately lead to even more challenging surgical procedures.