Central nervous system lymphoma in children.

This paper describes the rare MR and CT features of central nervous system (CNS) lymphoma in immunocompetent children and in survivors of childhood acute lymphoblastic leukemia (ALL) and discusses the causative role of cranial irradiation and/or leukoencephalopathy preceding central nervous system (CNS) lymphoma in survivors of childhood leukemia. The authors reviewed MR and CT scans of 3 children with biopsy-proved CNS lymphoma. One child had tumor infiltration within the optic nerve sheaths and optic chiasm by previously known non-Hodgkin lymphoma. In 2 patients, CNS lymphoma developed 8 and 10 years after initial ALL treatment. In both cases CNS lymphoma was preceded by cranial irradiation and leukoencephalopathy. A single lesion was present in 3 out of 4 patients. All lesions were isointense or hypointense on the T1-weighted images relative to gray matter and showed homogeneous enhancement. One lesion was centered in the central gray matter, one lesion was centered within a cerebral hemisphere, one lesion was in optic nerve, and there were 2 parasellar lesions. CNS lymphoma has a variable appearance in children. Knowledge of risk factors in children may help in the early recognition of disease, allowing for timely intervention. This may prompt early biopsy or a conservative management in the appropriate clinical setting.