Lymphomatosis cerebri: a treatable cause of rapidly progressive dementia

INTRODUCTION Lymphomatosis cerebri (LC) is a rare variant of primary central nervous system lymphoma (PCNSL) pathologically characterised by diffuse cerebral infiltration of a non-cohesive mass of malignant lymphoid cells. We describe a case of rapidly progressive dementia where MRI demonstrated a diffuse leukoencephalopathy. After a series of normal investigations, brain biopsy was undertaken with histology consistent with LC. Our patient was successfully treated with chemoradiotherapy and neurorehabilitation. This case underlines the importance of timely brain biopsy in rapidly progressive cognitive decline to allow earlier therapy for potentially curable pathology.