Primary Isolated Breast Lymphoma Presenting as Primary Breast Cancer with 18F-FDG PET/CT.

A 40-year-old woman with a palpable mass lesion in her right breast suggested as breast cancer was admitted to 18F-fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) unit for the metabolic characterization of the lesion and for the staging of the disease. The patient had no fever and no evidence of weight loss or night sweats. 18F-FDG PET/CT revealed an isolated solid mass lesion with increased 18F-FDG uptake in the upper outer quadrant of the right breast and increased 18F-FDG uptake in the lymph nodes of the right axilla suspected as primary breast cancer and its local lymph node metastasis. There was no other pathological 18F-FDG uptake in the whole body. Excisional biopsy histopathology revealed diffuse large B-cell non-Hodgkin lymphoma.