Differentiation of newly developed intracranial lesions after long-term management of non-germinomatous germ cell tumors (NGGCTs)

Abstract Intracranial germ cell tumor (iGCT) is a rare type of brain tumors which is prevalent among children and adolescents. Among iGCTs, non-germinomatous germ cell tumors (NGGCTs) presented with a poorer prognosis. Since treatment primarily involves chemotherapy and radiotherapy, it is crucial to differentiate treatment-related secondary tumors that may develop during follow-up from recurrences of iGCTs. However, there are few studies distinguishing between these two outcomes. Based on the criteria from SIOP trials, we identified 3 NGGCT patients from Peking Union Medical College Hospital (PUMCH) who achieved remission after initial treatment but developed new intracranial lesions upon long-term follow-up. We retrospectively analyzed the clinical characteristics, treatment, and prognosis of these 3 patients. At first, all 3 NGGCT patients presented with elevated tumor markers and intracranial lesions on MRI. After the initial treatment, all patients achieved clinical remission and were followed-up regularly. However, more than 5 years later, new intracranial lesions appeared on MRI in these 3 patients, with variated locations and changes in tumor markers. 1 patient was diagnosed with secondary meningioma, while the others were highly suspected as recurrences of iGCTs. All patients received timely and appropriate interventions. In conclusion, differentiating between tumor recurrence and secondary tumors during the follow-up of iGCTs requires a comprehensive assessment involving tumor marker patterns, imaging features, and pathological findings.