2024-07-292024-07-292023-08-17https://repository.tcu.edu/handle/116099117/65224Cancer of unknown primary (CUP) is a heterogeneous group of metastatic tumors in the absence of a clinically identifiable site. We describe the case of a 66-year-old female with an extensive history of non-specific imaging concerning for malignancy who did not undergo further workup and in whom a diagnosis of CUP was made. The patient initially presented to her specialist with concern of right leg pain. Imaging at that time was concerning for a progressive malignant process. Given this, the patient was referred urgently for surgery. Final surgical pathology and breast prognostic panel were consistent with metastatic breast carcinoma at that time. Follow-up imaging performed 1-week postoperatively did not show suspicious findings in either breast, further supporting a diagnosis of CUP. To this end, we highlight the importance of follow-up imaging but recognize the challenges facing healthcare professionals in navigating the ethical principles of nonmalificience and beneficence in diagnostic workup.en-USCancer of unknown primarymetastatic breast carcinomabreast carcinomabreast cancerfemale cancerArticle