The first case of Lynch syndrome associated penile cancer harboring a heterozygous PMS2 frameshift variant.

Introduction: Penile squamous cell carcinoma (PSCC) is a rare malignancy in men with poor survival in metastatic disease. Lynch syndrome (LS) is a cancer predisposition, autosomal-dominant, inherited disorder arises from loss of function variants in mismatch repair genes.

Case presentation: Here, we reported a PSCC patient who was suspected with LS caused by a heterozygous PMS2 D526Afs*69 variant. A 57-year-old male with PSCC underwent pelvic lymph node dissection and bilateral groin lymph node dissection due to metastatic disease. He has a family history of colon cancer and brain cancer. Comprehensive genomic sequencing of his tumor specimen identified 19 somatic mutations with a high tumor mutation burden (14.03 mutations per Mb) and a high frequency of microsatellite instability (MSI-H). Additionally, a germline PMS2 D526Afs*69 mutation was identified in the peripheral blood sample. Immunohistochemistry analysis showed complete loss of PMS2 and MLH1 expression in his tumor cells.

Conclusion: These observations provided evidence suggesting that PSCC could be part of the LS spectrum.