- No other identified causes of painful paresthesias existing before chemotherapy (e.g., radiation or malignant plexopathy, lumbar or cervical radiculopathy, pre-existing peripheral neuropathy of another etiology [e.g., B12 deficiency, AIDS, monoclonal gammopathy, diabetes, heavy metal poisoning amyloidosis, syphilis, hyperthyroidism, hypothyroidism, inherited neuropathy, etc.])