This is a case of relapsed non-Hodgkin lymphoma (NHL) on PET-CT presenting as diffuse, painless non-pitting left arm edema. Core biopsy was not definitive for diffuse large B-cell lymphoma (DLBCL) relapse, as it showed CD5 positivity, whereas previous DLBCL was CD5 negative. Palliative chemotherapy was commenced to reduce the disease burden.