Neurologic complications of lymphoma, leukemia, and paraproteinemias

Purpose of Review: This article reviews the spectrum of neurologic complications associated with lymphoma, leukemia, and paraproteinemic disorders. While leptomeningeal metastasis is the most common complication of lymphoma and leukemia and peripheral neuropathy is the most common complication of paraproteinemic disorders, clinicians need to be familiar with the diverse neurologic complications of these disorders. Recent Findings: Lymphomatous nervous system involvement can be difficult to diagnose, especially when it is the presenting symptom. CSF cytology and flow cytometry, as well as the imaging pattern, assist in diagnosis. Neurologic complications are less common in Hodgkin lymphoma; however, some unique paraneoplastic syndromes are associated with Hodgkin lymphoma, including primary central nervous system angiitis, limbic encephalitis, and cerebellar degeneration. Recent reports suggest that antiYmetabotropic glutamate receptor 5 (mGluR5) antibodies are associated with limbic encephalitis and that anti-Tr antibodies are associated with cerebellar degeneration in Hodgkin lymphoma. Polyneuropathy, organomegaly, endocrinopathy, monoclonal plasma cell disorder, and skin changes (POEMS) syndrome is often misdiagnosed as chronic inflammatory demyelinating polyradiculoneuropathy (CIDP). A lambda protein, thrombocytosis, and elevated vascular endothelial growth factor (VEGF) can all be helpful clues in diagnosis. Early recognition is important, as the neuropathy responds to radiation therapy or chemotherapy. Summary: Neurologic involvement can occur throughout the disease course in lymphoma and leukemia, including at presentation, with systemic progression, and at relapse. In paraproteinemias, the peripheral neuropathy phenotype, monoclonal protein type, and associated autonomic and systemic features aid in identification of an underlying plasma cell disorder.