縦線状爪甲白斑の2例とくに他種爪甲白斑との差異

TWO CASES OF LEUKONYCHIA STRIATA LONGITUDINALIS

　爪甲に白色線条が縦走する爪甲白斑はきわめてまれなもので，1925年にSiemens^1）が，1935年にLombardo^2）が報告した以外には文献的には記載がなく，爪疾患を扱つた教本^3,4）にも記載がない。最近著者らは爪甲に白色線条が縦走する爪甲白斑を2例経験したので報告し，爪甲白斑の組織学的所見について若干の考察を加える。

Leukonychia striata longitudinalis is reported of two cases in which a leukonychial streak persists in a finger nail for several years. In the first case, the whiteness of the nail plate is attributed to the presence of the abnormal cornifield cells which contain eosinophilic, PAS-positive and amylase digestive substances, accompanied by parakeratotic hyperplasia of the nail bed epidermis downwards into the dermis. In the second case, on the other hand, the whiteness of the nail plate is attributed just to parakeratotic hyperplasia of the nail bed epidermis up-wards into the nail plate.

The disturbance is probably due to nevoid changes at the distal portion of the intermediate nail matrix beneath the leukonychia. It is presumed that incomplete keratinization of the lower nail plate in the former as well as absence or decrease of the lower nail plate in the latter case causes a secondary hyperkeratosis in the nail bed epidermis.