Neurolymphomatosis (NL) is a rare peripheral or cranial neuropathy caused by non-Hodgkin's lymphoma (NHL). Diagnosis is often delayed and prognosis is poor. The authors described a woman in her 70s with a facial left peripheral palsy, complete right abducent palsy, left hypoacusia and balance deficit. Then she presented with low progressive hyposthenia at four limbs and cognitive impairment, sudden facial right peripheral palsy and complete left abducent palsy. The authors performed brain and spinal MRI, cerebrospinal fluid (CSF) analysis and extensive haematological examinations for infections, autoimmune and neoplastic diseases. All the results were not diagnostic. Only repeating for the third time a spinal tap, CSF presented neoplastic B cells suggestive for large B-NHL. The authors diagnosed primary NL. The patient was treated with R-CHOP but she died 2 months later. In front of rapidly progressive neuropathy, a NL has to be considered performing different examinations, especially and repeating them after a short period.