This case fulfills the criteria for multiple primary malignancies [1], as our patient was simultaneously diagnosed with invasive ductal breast carcinoma (ER+/PR+/HER2+, pT1cN0) and clear cell renal cell carcinoma (pT1aNxMx, G2) following treatment for HL at age 23 with ABVD and supradiaphragmatic radiotherapy. This evidence concerns the gene ESR1 and invasive ductal breast carcinoma.