Focal conduction block in a case of tarsal tunnel syndrome.

We report a case of tarsal tunnel syndrome (TTS) with focal conduction block across the tarsal tunnel (TT). A 46-year-old woman had pain in the left foot, sensory loss on the plantar surface, and positive Tinel sign over the TT. TTS was confirmed by magnetic resonance imaging (MRI) scan and surgery. Motor nerve conduction studies showed focal conduction block across the TT. Conduction block has rarely been reported in TTS. In this case, conduction block provides evidence for focal demyelination as the primary pathological process in TTS.