Skin biopsy

Small fiber neuropathy (SFN) is a common neuromuscular disorder which predominantly affects myelinated Aδ (delta) and unmyelinated C fibers and associated with several medical conditions. Routine nerve conduction study (NCS) and needle electromyography (EMG) are typically normal in SFN. The past two decades have seen the development of skin biopsy with intraepidermal nerve fiber density (IENFD) quantification. This specialized test has greatly facilitated the diagnosis of SFN and has been increasingly used by treating neurologists to evaluate patients with SFN. A growing number of diagnostic cutaneous nerve laboratories have been established, especially in the USA and Europe, to provide this useful diagnostic service. A task force of the European Federation of Neurological Societies (EFNS) published the first guideline paper regarding the use of skin biopsy in the diagnosis of SFN in 2005 (Lauria et al., Eur J Neurol 12(10):747-58, 2005), and a joint task force of EFNS and the Peripheral Nerve Society (PNS) published the second guideline paper in 2010 (Lauria et al., Eur J Neurol 17(7):903-12, 2010). This chapter is a brief review of the skin biopsy procedure, skin biopsy specimen processing and interpretation, and clinical utility of skin biopsy with intraepidermal and dermal nerve fiber density evaluation. A review of small fiber neuropathy is highcixlighted in Chap. 25. The readers may go to the two guideline papers for the in-depth review (Lauria et al., Eur J Neurol 12(10):747-58, 2005; Lauria et al., Eur J Neurol 17(7):903-12, 2010).