Capsule Summary
- •
Longitudinal melanonychia (LM) is a diagnostic challenge, as it may represent either a benign lesion or a nail matrix tumor.
- •
Dermatoscopic examination of the nail plate does not provide direct analysis of the nail matrix, which is the anatomic origin of the pigmentation.
- •
We have recently introduced intraoperative dermatoscopy, which is performed directly on the nail matrix after nail plate avulsion.
- •
This study establishes and validates 4 dermatoscopic patterns observed by using intraoperative dermatoscopy on patients with longitudinal melanonychia