Spontaneous Regression in Intracranial Germinoma: Case Report and Literature Review

BACKGROUND: Spontaneous regression in intracranial germ cell tumors (GCTs) is an extremely rare phenomenon with only 9 cases reported. The mechanism and natural history of this phenomenon are still equivocal. METHODS: A 12-year-old boy presented with a lesion in the suprasellar region with involvement of basal ganglia and corpus callosum. After 1 month, his symptoms were relieved, and magnetic resonance imaging demonstrated a remarkable regression of the lesion. Three months later, the boy's symptoms deteriorated, and magnetic resonance imaging revealed regrowth and enlargement of the lesion. Diagnosis of germinoma was confirmed via biopsy, and radiation therapy achieved complete response. We performed a systematic literature review of spontaneous regression of intracranial GCTs. The natural history of these cases was analyzed, and hypotheses in the studies were discussed. RESULTS: Spontaneous regression is extremely rare with only 10 cases reported, including the present case. There were 9 male patients and 1 female patient with mean age 22.1 +/- 10.3 years (range, 12-43 years). Nine cases were diagnosed as germinoma, and 4 cases included an episode of regression followed by regrowth. The mechanism of tumor regression in intracranial GCTs remains unclear. Four hypotheses were proposed, including radiation exposure, surgical procedures, effects of steroids, and immune reaction triggered by intervention. CONCLUSIONS: Tumor regression in intracranial GCTs could be a iatrogenic transient phenomenon, caused by complex immune reactions triggered by interventions.