Neurological examination: skin biopsy

Abstract

Using confocal laser scanning microscopy, we showed that intraepidermal nerve fibers in skin specimens obtained by skin biopsy were immunohistochemically stained by PGP 9.5 and ran through the epidermal intercellular space. With fixation conditions of 0.08 M phosphate buffer for transmission electron microscopy, we demonstrated the ultrastructure of the epidermis: little shrinkage of keratinocytes, interdigitations of microvilli, and four kinds of processes of keratinocytes, axons, melanocytes, and Langerhans cells in the spaces between keratinocytes. Axons had low electron density and few identifiable organelles without a basement membrane or Schwann cells, and were directly adjacent to the plasma membrane of keratinocytes. Unlike the other processes, axons did not have large intercellular spaces defined as intercellular clefts and the processes had circular or elliptical structures. Recently, skin biopsy for immunostaining with PGP 9.5 has become an indispensable diagnostic tool for small fiber neuropathy, and we discuss the significance based on our cases.