A Rare Case of Motor Neuropathy Secondary to Non-Hodgkin Lymphoma.

Neurological syndromes associated with lymphomas are uncommon. These syndromes occur mainly in Hodgkin lymphoma and primarily involve the central nervous system. Neurological manifestations in the peripheral nervous system and motor neuropathies are rare and add an extra layer of diagnostic confusion. We describe the case of a 70-year-old man with a history of right foot drop, who arrived at the emergency department after sustaining polytrauma. During initial evaluation, imaging studies incidentally revealed a retroperitoneal mass, which further studies diagnosed as an aggressive B-cell lymphoma with MYC mutation. After multidisciplinary evaluation, clinical findings supported the diagnosis of right peroneal nerve motor mononeuropathy as a paraneoplastic syndrome secondary to lymphoma. We describe the imaging findings, diagnostic workup, and clinical course that enabled recognition of this atypical association.