Thomas Luc, Dalle Stéphane
Service de Dermatologie, Université Lyon France and Hôtel Dieu de Lyon, Lyon Cedex France.
Dermatol Ther. 2007 Jan-Feb;20(1):3-10. doi: 10.1111/j.1529-8019.2007.00106.x.
The diagnosis of melanonychia striata is often difficult, and a biopsy of the nail matrix is required in doubtful cases. However, dermoscopic examination of the nail plate offers interesting information in order to better select the cases in which pathologic examination is indicated. In the case of brown longitudinal pigmentation with parallel regular lines, the diagnosis of nail apparatus melanocytic nevus could be made. On the other hand, the presence of a brown pigmentation overlaid by longitudinal lines irregular in their thickness, spacing, color, or parallelism is highly in favor of a melanoma. Gray homogeneous lines are observed in case of lentigo, lentiginoses, ethnic or drug-induced pigmentations, and in post-traumatic pigmentations. Blood spots are characterized by their round-shaped proximal edge and their filamentous distal edge and are highly suggestive of subungual hemorrhages. Dermoscopic examination of the free edge of the nail plate gives information on the lesion location; pigmentation of the dorsum of the nail plate is in favor of a proximal nail matrix lesion, whereas pigmentation the lower part of the nail edge is in favor of a lesion of the distal matrix.
甲黑线的诊断通常很困难，在可疑病例中需要对甲母质进行活检。然而，对甲板进行皮肤镜检查可提供有用信息，以便更好地选择需要进行病理检查的病例。对于伴有平行规则线条的棕色纵向色素沉着，可诊断为甲器黑素细胞痣。另一方面，如果存在被厚度、间距、颜色或平行度不规则的纵向线条覆盖的棕色色素沉着，则高度提示为黑色素瘤。在雀斑、雀斑样痣、种族性或药物性色素沉着以及创伤后色素沉着的情况下，可观察到灰色均匀线条。血斑的特征是近端边缘呈圆形，远端边缘呈丝状，高度提示甲下出血。对甲板游离缘进行皮肤镜检查可提供有关病变位置的信息；甲板背面色素沉着提示近端甲母质病变，而指甲边缘下部色素沉着提示远端甲母质病变。
