Summary

A 45-year-old Indian woman presented in neurosurgery outpatient with seizures, headache and vomiting for the past 1 month. MRI of the brain was suggestive of a malignant central nervous system (CNS) tumour. Histological and immunohistochemical examinations of stereotactic biopsy of the tumour were diagnostic of a low-grade diffuse small lymphocytic lymphoma of the CNS. No evidence of any occult systemic lymphoma was observed, confirming its ‘primary’ origin in the CNS. The diagnosis of a low-grade primary CNS lymphoma (PCNSL) is difficult as clinical and neuroradiological features are wide and variable. The clinical course is more indolent than a high-grade PCNSL and thus, a less aggressive and localised targeted treatment could be sufficient rather than the high dose, neurotoxic methotrexate-based chemotherapeutic treatment, recommended for high-grade PCNSL. Histological and immunohistological confirmation is therefore mandatory for early, appropriate treatment and prognostic implications.