The FDG PET/CT images of a patient with rapidly progressive cutaneous follicular lymphoma presenting general signs (a). CT scans showed cutaneous nodes and hilar lymph nodes. Bone marrow biopsy was negative. FDG PET/CT was realised in order to detect systemic lymphoma and to guide biopsy to detect aggressive transformation. FDG PET/CT shows high levels of fixation in subcutaneous nodes, especially in presternal area (with maximal SUV of 25) (b), in supra-and infradiaphragmatic lymph nodes (c) and in focalized bone foci (d). Biopsy realised in presternal area confirmed aggressive transformation of FL.