We present different clinical cases of patients with lymphoma of nervous system. We implemented
a protocol that could be useful in the process of diagnosing. The algorithm include: neurological exam, brain imaging examination (magnetic resonance imaging- MRI, computed tomography- CT), cerebrospinal fluid (CSF) testing with flow cytometry examination (FCM) and additionally biopsy. In the article we present more precisely five patients with different neurological symptoms. First case is of a 44-year-old male admitted to the hospital with meningeal irritation syndrome, with MRI data for tumour in the left cavernous sinus area. Biopsy was performed 3 months earlier negative histology for tumour cells. It was discussed CNS infection an examination of cerebrospinal fluid (CSF) showed lymphocytic pleocytosis with atypical lymphocytes. FCM of CSF showed T-lymphoblastic lymphoma. The second case is of 50-year-old female with complaints of weakness in the lower limbs, dysphagia and facial nerve palsy. MRI of the brain showed no pathology. The patient was with suspicion for Guillain-Barre syndrome due to symptoms and performed EMG. CSF examination showed lymphocytic pleocytosis. The patient was diagnosed with B-lymphoblastic lymphoma due to result from FCM of CSF. The third case is of a 63-year-old male with right hemiparesis. It was discussed ischemic stroke, tumour, CNS infectious disease and progressive cognitive impairment. MRI of the brain was performed with diffuse lesions in both hemispheres and left cerebellar peduncle. CSF examination showed no pathological changes. After brain tissue biopsy of one of the lesions the patient was diagnosed with diffuse large B-cell lymphoma. The fourth case is of a 71-year-old male with meningeal irritation syndrome, fever, diarrhea. CSF was with lymphocytic pleocytosis. CT of the abdomen was performed because of abdominal pain and weight reduction for several months. A tumour formation was found and biopsy of it showed B- cell lymphoma. The fifth case is of a 51- year-old male with headache and fever (38.5 degree Celsius). All test were negative, except FCM examination of CSF showing T- lymphoblastic lymphoma.