We report a case of a primary malignant lymphoma of the trigeminal nerve that was associated with facial pain. A 65-year-old man was examined at another hospital for unilateral facial pain. Carbamazepine was prescribed, but his symptoms did not improve. Magnetic resonance imaging (MRI) revealed swelling of the trigeminal nerve and a mass lesion in Meckel's cave. The patient was referred to our hospital at this point. Gadolinium-enhanced MRI and F18-Fluorodeoxyglucose-position emission tomography suggested a likely malignant tumour and a biopsy was performed. Histopathological examination showed diffuse a large B cell lymphoma. The patient was treated with high-dose methotrexate (HD-MTX) and radiotherapy. Despite responding well to initial treatment, the patient relapsed, with lymphoma observed throughout the body. He died of pneumonia 18 months after the initial diagnosis. Facial pain is a symptom that is commonly managed in general practice. If symptoms do not improve, repeated imaging studies, including contrast MRI, is warranted. This is the first reported case of primary neurolymphomatosis (NL) of the trigeminal nerve associated with facial pain alone. Furthermore, HD-MTX and radiotherapy may be considered for the management of primary NL of a cranial nerve.
Keywords: HD-MTX; Neurolymphomatosis; radiotherapy; trigeminal neuralgia.