Atypical Unilateral Lower-Limb Relapse of Breast Cancer

In July 2017, an 84-year-old woman was treated for grade III, RH+, HER2- infiltrative ductal carcinoma breast cancer by right mastectomy, adjuvant radiotherapy, and hormone therapy. In April 2020, moderated elevation of the CA-15.3 tumor marker was observed at 53 UI/mL (normal, <25.5 UI/mL). Clinical examination and CT TAP scan showed no argument for relapse. In August 2020, patient presented pain in her left foot. 99mTc-DPD bone scintigraphy showed multiple uptakes regarding osteolytic lesion of the left lower limb with no other pathological uptake. Echo-guided tibial biopsies confirmed breast origin adenocarcinoma, in favor of relapse of the originally treated cancer.