[Resistance to first line chemotherapy treatment in a patient diagnosed of nodular lymphocyte-predominant Hodgkin's lymphoma identified by 18F-FDG PET/CT: diagnostic and therapeutic implications].

Nodular lymphocyte-predominant Hodgkin lymphoma (NLPHL) is a rare entity that accounts for less than 5% of the cases of Hodgkin lymphoma (HL) with morphological, immunophenotypical, genetic and clinical behavior traits different from the classic HL. In a minority of patients, the NLPHL course is complicated by a transformation to a non-Hodgkin diffuse large B-cell lymphoma (NHDLBCL) with prognostic and therapeutic implications. Early metabolic changes observed by (18)F-FDG PET in patients with HL and NHL, after 1-3 cycles of chemotherapy, predict the final response to treatment and progression-free survival. In the case we are presenting herein, whether NLPHL is transformed to NHDLBCL or the two types of lymphoma co-exist in the same patient, the (18)F-FDG PET/CT scan was crucial for the identification of tumor resistance to first line chemotherapy and to guide a second biopsy decision and therefore modify the chemotherapy regimen.