Mutations in the BRCA1 and BRCA2 genes significantly increase the risk of hereditary cancers, mainly of the breast and ovary, but also of other cancers such as those of the pancreas, prostate and cervix. In carriers of these mutations, multiple primary malignancies (MPM) represent a complex clinical challenge, influenced by genetic and environmental factors, as well as previous cancer treatments. The case reports a patient with a BRCA1 mutation with a family history of breast and ovarian cancer and who developed cervical cancer then recurrent triple-negative breast cancer treated with mastectomy, radiotherapy, chemotherapy and Poly (Adenosine diphosohate-ribose) polymérase inhibitors. This case underlines the interplay between different malignancies in the context of breast cancer mutations and the importance of specific and personalised treatment of patients with multiple primary malignancies.