A wart or something more sinister?
It also involved the nail matrix resulting in a partially dystrophic nail.
The most likely diagnosis is a wart but the patient had no sign of warts elsewhere. Two other conditions to consider would be a squamous cell carcinoma or an amelanotic melanoma. The latter is unlikely but even the remote possibility means that some tissue here should be submitted for histology.
The nail was removed under a ring block and the other warty tissue curetted away with both nail and curettings sent for histology. It turned out to be a wart.