Bilateral synchronous testicular neoplasms of different lineages: A germ cell tumour and a sex cord-stromal tumour. A case report.

Bilateral testicular tumours are uncommon, and synchronous presentations involving different histogenetic lineages are rarely reported in the literature. Most bilateral tumours are metachronous and of germ cell origin. The coexistence of a malignant germ cell tumour in one testis and a benign sex cord-stromal tumour in the contralateral testis is an unusual finding with diagnostic and therapeutic implications. We present the case of a 45-year-old man who underwent bilateral radical orchiectomy after ultrasonography identified three nodules in the left testis (maximum diameter 24mm) and a 7mm lesion in the right testis, with tumour markers within normal ranges. Histopathological examination showed a multifocal classic seminoma confined to the left testis and a Leydig cell tumour confined to the right. Immunohistochemical analysis confirmed distinct lineages. This case highlights the importance of thorough histopathological evaluation in guiding clinical management.