18FDG PET/CT IN PRIMARY AND SECONDARY CNS LYMPHOMAS

Abstract

Primary central nervous system lymphoma (PCNSL) is an aggressive form of Non-Hodgkin’s Lymphoma (NHL) which involves predominantly brain and less commonly spinal cord, eye and leptomeninges and localized to CNS only. PCNSL accounts for about 1% of all non-Hodgkin lymphomas (NHL, mainly diffuse large B-Cell) and for approximately 2% of all CNS tumors.¹ PCNSL has different etiology in immunocompetent and immunocompromised patients.² In the majority of HIV-positive and transplant recipient cases, PCNSL is associated with Epstein-Barr virus, whereas Epstein-Barr virus associated PCNSL is uncommon in immunocompetent subjects.² When lymphoma has originated in other parts of the body and subsequently has spread to the CNS, it is referred to as secondary CNS lymphoma (SCNSL). Therefore, in case of histopathologically proven CNS lymphoma according to clinical oncological guidelines, contrast-enhanced chest and abdominopelvic CT or whole-body 18-fluorodeoxyglucose (¹⁸FDG) positron emission tomography/computerized tomography (PET/CT) is standardly indicated to exclude the secondary brain involvement by systemic lymphoma.