[Hyde's nodular prurigo: an electronmicroscopic study]

Electron microscopic studies were carried out on cutaneous lesions in one case of prurigo nodularis Hyde. The cells of the basal layer partly showed large paranuclear vacuoles, which were sometimes divided by thin membrane structures. The intercellular space of the stratum basale and stratum spinosum was usually dilated, exhibiting acantholytic phenomen. Furthermore, numerous cells of these layers contain vacuolic-like mitochondria and polymorphous granular structures. Melanocytes and Langerhans-cells have not been observed, however, Merkel-cells were found in the basal layer, containing characteristic electrondense granules measuring 80 to 100 nm in diameter. The stratum granulosum frequently showed large intercellular complexes of numerous desmosomes, which sometimes were forming desmosomal bridges crossing the intercellular space. The capillaries in the dermis were usually widened and frequently surrounded by edematous alterations. The cytoplasm of the endothelial cells appeared very electrondens. Numerous unmyelinated axons were observed within the subepidermal zone containing mitochondria and single granules, measuring 80 to 100 nm in diameter.