Paraneoplastic syndromes are the rarest neurological complications in patients with breast cancer. Here, we present a case of occult breast cancer presenting as paraneoplastic sensory neuropathy. A 47-year-old woman developed progressive upper and lower extremity weaknesses with paresthesia and gait ataxia. Multiple cerebrospinal fluid (CSF) analyses and magnetic resonance image (MRI) scans of her brain and spine offered no diagnosis. Although no paraneoplastic antibodies were found, paraneoplastic neurological syndrome was suspected after examination by the neurologist eliminated other possibilities. Her mammogram demonstrated pleomorphic calcifications. Although local and systemic therapies were given, no significant improvement in the neurologic condition was found.