Osseous metastasis in jaws is an unusual clinical event. A 43-year-old woman with a medical history of breast cancer diagnosed in 2017 was treated with total mastectomy. Bone scintigraphy showed no metastasis after initial treatment. However, in 2020, the patient noted pain during mastication in molar right area. The tooth 48 was removed, and antibiotics were prescribed. Due to persistent and more severe pain, she was referred to an oral medicine clinic. The intraoral examination revealed a localized soft tissue exophytic mass involving 46/47 gingival area. The computed tomography showed a bilateral, osteolytic, and ill-defined lesion in the posterior mandibular area. An intraosseous incisional biopsy was performed in the right retromolar area. The histopathologic (H.E) and immunohistochemical exams confirmed a metastasis of breast cancer in the jaw. After 5 sessions of a combined treatment with CMF and zoledronic acid, a partial resolution of the tumor was observed. Osseous metastasis in jaws is an unusual clinical event. A 43-year-old woman with a medical history of breast cancer diagnosed in 2017 was treated with total mastectomy. Bone scintigraphy showed no metastasis after initial treatment. However, in 2020, the patient noted pain during mastication in molar right area. The tooth 48 was removed, and antibiotics were prescribed. Due to persistent and more severe pain, she was referred to an oral medicine clinic. The intraoral examination revealed a localized soft tissue exophytic mass involving 46/47 gingival area. The computed tomography showed a bilateral, osteolytic, and ill-defined lesion in the posterior mandibular area. An intraosseous incisional biopsy was performed in the right retromolar area. The histopathologic (H.E) and immunohistochemical exams confirmed a metastasis of breast cancer in the jaw. After 5 sessions of a combined treatment with CMF and zoledronic acid, a partial resolution of the tumor was observed.