PET has an established role in the management of breast cancer. However, F-18 FDG uptake sometimes has been associated with benign disease leading to false positive results. We present a case of a 37-year-old woman who presented with a 3-month history of a left breast lump and palpable left axillary lymph nodes. Whole-body PET-CT scan demonstrated multiple focal areas of intense FDG uptake in the left breast and multiple axillary, cervical, and mediastinal lymph nodes. PET-CT findings mimicked metastatic breast cancer, which was subsequently confirmed as disseminated tuberculosis by mammotome-guided biopsy of the breast lesion and fine needle aspiration biopsy of lymph nodes.