Primary Breast Lymphoma Mimicking Metastatic Breast Cancer on 18F-FDG PET-CT

18F-Fluorodeoxyglucose (FDG) PET-CT is an excellent imaging modality for the evaluation of non-Hodgkin lymphoma (NHL). We report a case of a 45-year-old woman presented with a large right breast mass and suspicious right axillary lymph nodes referred for 18F-FDG PET-CT for staging. 18F-FDG PET-CT images show large hypermetabolic right breast mass infiltrating the skin, multiple hypermetabolic right axillary and subpectoral lymph nodes, along with multiple hypermetabolic bone lesions at axial and appendicular skeleton. Findings are mimicking primary breast cancer with nodal and bone metastases. Biopsy revealed diffuse large B cell lymphoma. 18F-FDG PETCT is helpful in evaluation of disease extent and response evaluation of primary breast lymphoma.