A case of primary ovarian clear cell carcinoma with ETV6::NTRK3 fusion.

We report the first documented case of primary ovarian clear cell carcinoma harboring an ETV6::NTRK3 fusion gene. A 49-year-old woman presented with a rapidly growing ovarian cyst that was diagnosed as stage IC1 clear cell carcinoma following primary debulking surgery. Molecular analysis revealed an ETV6::NTRK3 fusion gene, confirmed by RT-PCR and Sanger sequencing. The tumor also contained an ARID1A variant (p.P1326Rfs*155), exhibited low tumor mutation burden (3.7 Muts/Mbp), and showed stable microsatellite status. Following standard surgical and chemotherapeutic treatment, the patient remained disease-free at 2.5 years post-surgery. This case demonstrates that NTRK fusion gene, in conjunction with ARID1A mutation, may contribute to clear cell carcinoma development, highlighting the need for further investigation into the prevalence and significance of NTRK fusions in ovarian clear cell carcinomas. The identification of this actionable genetic alteration provides potential targeted therapeutic options should disease recurrence occur.