# Targeting mutant VHL-gene results in therapy response in metastatic clear cell carcinoma of rete testis

## TL;DR

A rare testicular tumor with VHL gene mutation responded to targeted therapy, showing the value of genetic profiling in personalized cancer treatment.

## Contribution

Demonstrates successful off-label use of belzutifan in a rare tumor with VHL mutation through molecular profiling.

## Key findings

- A patient with metastatic rete testis carcinoma showed regression after treatment with belzutifan.
- Molecular profiling identified pathogenic VHL and TP53 variants guiding targeted therapy.
- Complete remission was maintained for 12 months following treatment initiation.

## Abstract

Epididymal and rete testis tumors are exceedingly rare. We report a 69-year-old male who presented with progressive swelling of the right testis/epididymis; histopathology confirmed clear cell carcinoma of the rete testis. Staging with FDG-PET-CT revealed bilateral pulmonary metastases. Subsequent gene panel sequencing identified a pathogenic variant of VHL and a likely pathogenic variant of TP53. Off-label treatment with belzutifan was initiated. Regression of the pulmonary lesion with ongoing complete remission at 12 months of follow-up was observed. This case highlights the importance of molecular profiling for personalized therapy in rare tumor entities.