RESUMO
INTRODUCTION: Multiple primary cancers (MPCs) have attracted attention in medical research due to their increasing incidence. The coexistence of invasive breast carcinoma and clear cell carcinoma of the kidney, alongside a family history of cancer, highlights the multifactorial origins of MPCs, particularly their potential association with genetic factors. CASE PRESENTATION: A 70-year-old female initially sought medical attention for a two-year history of a right breast lump as her primary concerns centered on the long-standing lump. Clinical evaluations and imaging studies revealed an invasive breast carcinoma diagnosis, and simultaneously, an incidental mass in her left kidney was identified as clear cell carcinoma. DISCUSSION: Emphasis and further researh should be on the potential role of genetic factors in MPC development, necessitating comprehensive genetic evaluations. CONCLUSION: This study highlights the significance of customized treatment approaches for each malignancy, facilitating early detection, improved patient outcomes, and an enhanced understanding of MPCs.