[A case of Castleman disease accompanying neuropathy only detected by S-SEP in the tibial nerve].

A 77-year-old woman was admitted with a chief complaint of tingling sensation in the both feet, which gradually developed just after the diagnosis of Castleman disease was made. Neurological examination showed mild weakness in the neck and pelvic girdle muscles, and sensory impairment affecting all modalities in the lower legs. Although these neurological findings suggest a diagnosis of neuropathy, nerve conduction studies (NCS) and F-wave disclosed no abnormalities. However, the short latency somatosensory evoked potential (S-SEP) in the tibial nerve revealed a significant delay in the P15 latency, which is indicative of neuropathy affecting proximal potion of the peripheral nerve. To our knowledge, only a few reports described proximal neuropathy associated with Castleman disease. In our case, the examination of S-SEP was very informative to make a diagnosis of neuropathy.