New PET-positive lesions in previously treated patients with lymphomatous malignancies need further investigations. Relapse, sarcoidosis and secondary malignancies are the most important differential diagnosis. Inflammatory myofibroblastic tumors (IMT) is a rare complication after treatment of Hodgkin's disease and every PET-positive lesion should be biopsied to prevent unnecessary intervention.
Keywords: Hodgkin's lymphoma; inflammatory myofibroblastic tumor; inflammatory pseudotumor; plasma cell granuloma; relapse.