Objective: To describe a case of breast carcinoma metastasis combined with pulpitis-like pain complaints in a mandibular molar. Although metastasis from distant sites to the mandible is unusual, it should be considered in the differential diagnosis of patients referred for endodontic treatment. Summary: A 54-year-old female with carcinoma of the breast was referred to the endodontic department for root canal treatment of tooth 47. After endodontic treatment, her pain disappeared, but periodontal problems persisted. Because hypoesthesia of the lip and chin, in combination with periodontal complaints, were noticed during follow-up appointments, a more aggressive process was suspected. Additional investigations with cone beam computed tomography (CBCT) and magnetic resonance imaging (MRI) revealed a metastasis in the mandibular molar area. Metastatic carcinomas may rarely mimic pulpal or periapical pathology. Failure to diagnose them may result in serious consequences for the patient. Patients with a history of malignancy and suffering from oral pain that is not completely resolved after therapy should undergo specific diagnostic tests to exclude a neoplastic aetiology for their symptoms. Interpretation: Follow-up of endodontic treatments is necessary to see if symptoms dissolve and to consider if the diagnosis should be modified. Endodontists are well qualified to detect oral metastases. Metastases from distant sites to the oral cavity are uncommon, but should be considered in the differential diagnosis. Keywords: endodontic diagnosis, endodontic-periodontal relations, metastasis Conflict-of-interest statement: The authors declare there are no conflicts of interest in this study.