The peripheral nerve is usually spared in chronic immune sensory polyradiculoneuropathy (CISP) according to a literature review; however, an extended-spectrum of CISP, CISP-plus, was introduced recently. Here we report a 29-year-old Taiwanese man who presented with numbness and hypoesthesia in all distal extremities, tightness sensation in the left posterior thigh, and sensory ataxia for three months. The clinical and neurophysiological examinations revealed proximal sensory abnormalities along with sural nerve involvement. The elevated protein level of cerebrospinal fluid (CSF) was noted and enlarged dorsal root ganglia were seen on the magnetic resonance imaging (MRI) of the whole spine. Autoimmune workup showed only positive human leukocyte antigen (HLA)-B27. Biopsy of the sural nerve revealed inflammatory demyelinating neuropathy. Only mild improvement was noted after methylprednisolone pulse therapy (1,000mg/day) for three days, and he was then treated with intravenous immunoglobulin with the dosage of 2g/kg-BW followed by azathioprine, and objective improvements were reported. Different from the previous case reports, CISP may also associate with peripheral nerve involvements. A sural nerve biopsy could assist the diagnosis. Further investigation is needed for the possible immune association between CISP-plus and HLA-B27.