A xanthogranulomatous process resembling residual disease on end of-Treatment 18f-FDG-PET/CT and Whole Body Magnetic Resonance performed on a primary breast lymphoma treated by ibrutinib plus rituximab-chop

We report the case of a woman, affected by breast diffuse large B-Cell lymphoma, who developed a xanthogranulomatous process wrongly interpreted as residual disease on 18F-FDG-PET/CTand Whole Body Magnetic Resonance after treatment with ibrutinib plus standard immunochemotherapy. Newer drugs, such as immunomodulatory agents and checkpoint inhibitors, have demonstrated high effectiveness on lymphoma, but are associated with unclear imaging features such as tumor flare or pseudo-progression, related to inflammatory reactions. Wide imaging techniques availability improves diagnostic possibilities. However, the awareness of the adopted treatment strategy and its possible implications on imaging features is crucial to make a correct response assessment.