Background: Isolated primary neurolymphomatosis (NL) of cranial multineuritis is a very rare condition that refers to the lymphomatous invasion of cranial nerves only. There are sparse cases of isolated cranial nerves NL reported worldwide.
Case presentation: We present magnetic resonance imaging (MRI) and cerebrospinal fluid (CSF) findings of a 63-year-old female patient suffering from isolated neurolymphomatosis of cranial multineuritis with a wide constellation of syndromes including binocular diplopia, left facial paralysis and pain, syncope episodes, and progressive dysphagia. A contrasted MRI brain showed multiple cranial nerves enhancement. Extensive workup for infectious, autoimmune, neoplastic, paraneoplastic, or inflammatory etiologies had been unrevealing except CSF cytology revealed large atypical monotypic B cells that were suspicious for non-Hodgkin lymphoma on the third large volume tap. The decision of biopsy was deferred after the risks and benefits discussion. Following the four cycles of empiric methotrexate-based induction chemotherapy, the patient's symptoms resolved, and a complete radiographic response was achieved without whole-brain radiation or autologous hematopoietic cell transplantation. In the latest follow-up, she is independent with her daily activities and remains in clinical and radiographic remission more than 3 years since initial chemotherapy.
Conclusion: Isolated NL of cranial nerves can present diagnostic and management pitfalls for the neurologist, neurosurgeons, and oncologists. Since current diagnostic modalities have modest sensitivity and a pathological diagnosis is often difficult, empiric treatment once other possibilities are ruled out can carry a good prognosis.
Keywords: CNS lymphoma; Cranial neuritis; Neurolymphomatosis.