Double Hit in Clear-Cell Renal Cell Carcinoma With Germline Pathogenic ATM Mutation and Somatic VHL Mutation.

While renal cell carcinoma (RCC) is often linked to smoking, obesity, and hypertension, hereditary forms also account for about 3% of RCC cases. Notably, NCCN guidelines identify 7 major hereditary syndromes associated with an increased RCC risk. Inherited mutations in DNA repair genes, such as ATM, BRCA, and TP53, significantly increase the risk of various cancers. Biallelic pathogenic mutations in ATM cause Ataxia-Telangiectasia (A-T) syndrome, while heterozygous germline pathogenic ATM mutations, present in about 1% of the population, also elevate cancer risk. RCC has not traditionally been associated with germline pathogenic ATM mutations, only limited retrospective analyses have identified such mutations. This case report presents a 68-year-old woman with a germline pathogenic ATM mutation (c.8786+1 G>A) who developed high-risk clear cell RCC followed by an acquired somatic VHL mutation in RCC and a 3-cm serous cystadenoma, illustrating the double-hit phenomenon. Her brother, who shares the same germline pathogenic mutation, was diagnosed with pancreatic cancer and prostate cancer. This case highlights the potential use for enhanced screening protocols for RCC in patients who have germline pathogenic ATM mutations and the importance of research in targeted treatments for tumors driven by dual genetic mechanisms. Increased awareness and vigilant screening for RCC are crucial in managing hereditary cancer syndromes effectively.