Synchronous Seminoma of Testis and Renal Cell Carcinoma: A Rare Case Report

<i>Background and Objectives</i>: Seminoma is the most common solid malignant tumour in young men. Clear-cell kidney carcinoma is the most common malignancy of the genitourinary tract. However, the synchronous occurrence of both of these tumours is rare. <i>Case presentation:</i> We present the case of a 36-year-old patient who presented to a medical facility at the end of 2019 with an enlarged right testicle. A unilateral orchofuniculectomy was performed, and a mass measuring 30 cm was removed. During histological examination, testicular seminoma pT2, R0, was diagnosed. An abdominal computed tomography (CT) scan showed a 6.4 cm × 6.8 cm × 6.7 cm tumour in the right kidney and a metastatic-like lesion in the right adrenal gland. A right nephrectomy and an adrenalectomy and paraaortic and paracaval lymphadenectomies were performed. A histological evaluation confirmed the presence of clear-cell renal carcinoma pT2aR0 G2, adrenal hyperplasia, and seminoma metastases in the removed lymph node. Chemotherapy with a Bleomycin, Etoposide, and Cisplatin (BEP) regimen was carried out. Three years after the last cycle of chemotherapy, a follow-up CT scan showed metastases in the left kidney, the right ischium, and the right lung. A well-differentiated clear-cell carcinoma G1 of the left kidney and metastasis of clear-cell carcinoma G2 in the right ischium were confirmed after the biopsy, and no tumour lesions were found in the lung tissue specimen. Treatment with targeted therapy with Sunitinib was started because the risk was favourable according to the Heng criteria. Genetic testing was performed, and the following genes were analysed: <i>VHL</i>, <i>BAP1</i>, <i>CHEK2</i>, <i>FH</i>, <i>MET</i>, <i>MUTYH</i>, <i>APC</i>, and <i>STK11.</i> The testing did not reveal any pathogenic or potentially pathogenic mutations or sequence changes of unknown clinical significance in the genes analysed. <i>Conclusions</i>: According to the authors, the occurrence of synchronous primary tumours is linked to one's genetic predisposition. DNA sequencing of tumour tissue could provide more information on the corresponding aetiopathogenesis.