Behavioral Changes as the Initial Presentation of Primary Central Nervous System Lymphoma: A Case Report

Brain tumors typically present with headaches, nausea, vomiting, seizures, or focal neurological deficits. However, neuropsychiatric manifestations, such as personality change and behavioral disturbance, may be the earliest signs, particularly when the frontal or temporal lobes are involved. We describe a 69-year-old man who presented repeatedly to his general practitioner (GP) with progressive behavioral changes and intermittent headaches. Initial investigations were unremarkable, and he received cognitive-behavioral therapy without improvement. He later developed facial deviation and limb numbness. Computed tomography (CT) of the head revealed a large, right-sided, space-occupying lesion, subsequently confirmed by magnetic resonance imaging (MRI) to be an intracranial tumor. Histopathology following biopsy confirmed primary central nervous system lymphoma (PCNSL). This case highlights the importance of considering intracranial pathology in patients with persistent or unexplained behavioral changes and underscores the role of early neuroimaging in preventing diagnostic delays.