Lymphoma of Nervous System or the Great Imitator in Neurology

Background: Lymphoma of the central nervous system (CNS), both primary and secondary, represents a very rare part of patients with non-Hodgkin lymphoma. Methods: Exams included a neurological exam, laboratory blood tests, МRI, biopsy, and electromyography. Results: Three different clinical cases of patients with lymphoma of the nervous system are presented. The first patient is a 44-year-old male admitted to the emergency room because of neck stiffness, with MRI data for a tumour in the left cavernous sinus area. Biopsy was performed 3 months prior to hospitalisation, showing connective tissue, partially hyalinised. Lumbar tap was performed to exclude CNS infection. Cerebrospinal fluid (CSF) examination showed lymphocytic pleocytosis, atypical cells in different phases of mitosis, and the result did not confirm lymphocytic choriomeningitis. Flow cytometric measurement (FCM) of CSF led to the diagnosis of T-lymphoblastic lymphoma of CNS. The second patient is a 50-year-old female hospitalised in the authors’ neurological department because of lower limb weakness and decreased sensation, dysphagia, and facial nerve palsy. Brain MRI showed no abnormal lesions. Guillain–Barré syndro