Description: Linear defect on nail

History:

 This lesion on one thumb nail had slowly developed over 1 year. It was asymptomatic. The yellow and white keratin lines with the proximal looped vessels and distal haemorrhages are characteristic of an early onychomatricoma. There was not yet a overcurvature of the nail or prominant distal nail edge tubules. 

This benign nail matrix tumour will require partial matrix excision. 

Look at this article in the DOJ for a more florid case with histology.