A condition of primary brachial nerve plexus lymphoma in a 73-year-old male is described. The tumor presented with solitary brachial nerve mass and treated with surgical excision, which led to a diagnosis of non-Hodgkin lymphoma, diffuse large cell type. The patient was treated with chemotherapy and radiotherapy, but presented unique clinical course that lymphoma relapsed mainly in the nervous system. Finally 20 months after the onset, the patient died. An autopsy showed lymphoma infiltration mainly in the nervous systems, such as left brachial nerve plexus, meninges, spinal ganglions, facial and sciatic nerves.
