[Primary malignant non-Hodgkin's lymphomas of the central nervous system in immunocompetent patients: diagnostic, prognostic and therapeutic criteria].

Primary central nervous system non-Hodgkin's malignant lymphomas (PCNSNHML) have undergone a remarkable increase in incidence in the last years. Clinically PCNSNHML may present with the symptoms that mimic many others neurological conditions. Radiologically they appear as iso or hyperdense deposits, often multiple, usually supratentorial in periventricular region. Histologically although most lesions are high grade B cell lymphomas, T cell lymphomas are being recognised with increasing frequency. Actually a substantial improvement in survival has been obtained using chemotherapy as sole treatment, eventually followed by radiotherapy for recurrences. The prognosis, however, remains poor in comparison with nodal lymphomas. It is improved by T-cell phenotype, a Karnofsky performance status more than 50%, age at onset less than 50 years and negativity for bcl-2 oncogene of neoplastic cells.