Melanonychia - 黑甲症
观察到不寻常的多行。 黑甲症 (Melanonychia) 大多是良性的，但如果这个级别有许多不规则的线条，则可以考虑进行活检。
Muehrcke's lines
References
许多患者对黑甲症感到担忧，因为它会导致指甲板变成棕黑色。这是指甲变色的常见原因，其原因从良性到潜在严重的，如黑色素瘤。纵向带状黑甲症可能源于各种局部或全身因素。
Melanonychia is a very worrisome entity for most patients. It is characterized by brownish black discoloration of nail plate and is a common cause of nail plate pigmentation. The aetiology of melanonychia ranges from more common benign causes to less common invasive and in situ melanomas. Melanonychia especially in a longitudinal band form can be due to both local and systemic causes.
Melanonychia is a very worrisome entity for most patients. It is characterized by brownish black discoloration of nail plate and is a common cause of nail plate pigmentation. The aetiology of melanonychia ranges from more common benign causes to less common invasive and in situ melanomas. Melanonychia especially in a longitudinal band form can be due to both local and systemic causes.
Melanonychia represents a brown to black discoloration of the nail plate that may be induced by benign or malignant causes. Two main mechanisms are involved in the appearance of melanonychias, i.e., melanocytic activation and melanocytic hyperplasia.
甲周组织上有一条宽而深的色素带，具有不规则的线条和色素延伸，是黑色素瘤的征兆。