# Next-generation sequencing of primary testicular lymphoma and relapse in the glans penis after prophylactic radiation therapy: a rare case report

## TL;DR

A rare case of testicular lymphoma relapse in the glans penis is reported, confirmed through genomic analysis.

## Contribution

This is the first documented case of primary testicular lymphoma relapse occurring in the glans penis.

## Key findings

- Genomic analysis showed the same variant allele fractions in four genes, indicating a shared origin between the testicular and penile lymphomas.
- The case highlights an unusual relapse site for primary testicular lymphoma despite prophylactic radiation therapy.

## Abstract

Primary testicular lymphoma (PTL) is relatively rare. The contralateral testis is a common site of PTL relapse; therefore, once complete remission is achieved, radiation therapy (RT) is administered to the contralateral testis to prevent relapse.

A 76-year-old man was diagnosed with PTL and received RT as described above. However, despite achieving and maintaining complete remission, a mass diagnosed as diffuse large B-cell lymphoma by tissue biopsy developed in the glans penis 6.5 years after prophylactic RT. We investigated whether the glans penile lymphoma was PTL relapse or a new malignancy by genomic analysis using next-generation sequencing of DNA extracted from two histopathological specimens.

We found the same variant allele fraction in four somatic genes (MYD88, IL7R, BLNK, and FLT3) at similar frequencies, indicating that the glans penile lymphoma had the same origin as the PTL. To the best of our knowledge, this is the first case report of PTL relapse in the glans penis.

The online version contains supplementary material available at 10.1186/s13000-024-01498-x.