I think they are the same thing. I've not heard the term small cell neuropathy but this may be what is meant but I'm not sure.

"What is another name for small fiber neuropathy? Small fiber sensory neuropathy (SFSN) is a disorder in which only the small sensory cutaneous nerves are affected." --- Small Fiber Sensory Neuropathy - Johns Hopkins Medicine: https://www.hopkinsmedicine.org/neurology_neurosurgery/centers_clinics/peripheral_nerve/conditions/small_fiber_sensory_neuropathy.html