Metastatic Testicular Germ Cell Tumor in a Patient With Neurofibromatosis Type 1: Treatment With Trametinib Based on NF1 Gene Mutation.

INTRODUCTION

Neurofibromatosis type 1 (NF1) is a genetic disorder that increases the risk of various tumors. However, its association with testicular germ cell tumors (GCTs) is rare. We report a case of metastatic GCT in an NF1 patient treated with precision medicine.

CASE PRESENTATION: A 40-year-old male with NF1 presented with a left testicular non-seminomatous GCT and lung metastases. The tumor showed progressive disease after chemotherapy (VIP, TGP) and surgical removal of metastases. Comprehensive genomic profiling (CGP) test found a pathogenic NF1 frameshift mutation (p.Q514fs*43). Based on this finding, the patient received the MEK inhibitor trametinib under patient-proposed healthcare services (BELIEVE Trial). Treatment resulted in normalization of serum alpha-fetoprotein (AFP) for 6 months before the tumor eventually progressed. The patient died at 39 months after diagnosis.

CONCLUSION

This is the first report of trametinib for a metastatic GCT with an NF1 mutation, suggesting a possible but limited treatment effect.

TRIAL REGISTRATION: The prospective trial of patient-proposed healthcare services with multiple targeted agents based on the results of gene profiling by multigene panel test (BELIEVE), NCCH1901/jRCTs031190104.