A patient with heterochronous double primary tumor of basal ganglia germ cell tumors followed by diffuse hemispheric glioma: a case report.

Background: Basal ganglia germ cell tumor (BGGCT) is a rare central nervous system (CNS) tumor. Diffuse hemispheric gliomas, H3 G34-mutant (DHGs) is an invasive glioma involving the cerebral hemispheres. The diagnosis of DHGs depends on the integration of histopathology and molecular pathology.

Case report: We reported a patient with an initial diagnosis of BGGCT that was sensitive to subsequent chemoradiotherapy. Unfortunately, a second high-grade glioma was found on magnetic resonance imaging (MRI) six years later. Subsequently, the tumor was completely removed after surgery and the following histopathology plus next generation sequencing (NGS) testing confirmed the diagnosis of DHGs. Interestingly, we found a germline likely pathogenic variant in FANCA. After surgery, the patient received Stupp regimen. The patient had a relapse 13 months after the Stupp regimen and was doing well after surgery.

Conclusions: This is the first report of a patient with heterochronous double primary tumor of BGGCT followed by DHGs.