Primary central nervous system lymphoma with lymphomatosis cerebri in an immunocompetent child: MRI and 18F-FDG PET-CT findings.

Primary central nervous system lymphoma (PCNSL) is extremely rare in immunocompetent children. We present the magnetic resonance imaging (MRI) and (18)F-fluorodeoxyglucose ((18)F-FDG) positron emission tomography-computed tomography (PET-CT) findings of such a case in a 14-year old immunocompetent boy. In this patient, PCNSL was associated with lymphomatosis cerebri. Familiarity with the findings of this rare condition will improve the diagnostic confidence of the nuclear radiologist and avoid misdiagnosis.