We report the case of a 70-year-old woman who presented with a small and painless red skin nodule in the right lower leg, which rapidly and significantly increased in size over few weeks and developed a central eschar. Skin biopsy was consistent with primary cutaneous diffuse large B-cell lymphoma, leg type (PCDBCL-LT), an aggressive and rare cutaneous lymphoma. F-FDG PET/CT showed a hypermetabolic soft tissue mass in the right leg with no evidence of systemic involvement of disease.