Does nodular melanoma have an in-situ phase? is it ever caught in-situ?

You can find melanom: in situ, which means it has not penetrated past the top layer of skin or epidermis

Nodular Melanoma: At the earliest detection and treatment nodular melanoma may have a cure rate of 95%. People should remember that not all melanoma develops in a changing mole. It may also appear from a previous lesion and may look like an awkward scar or cyst. It may also appear like a non-healing bruise or nail streak.

Yes: In situ is the first level of melanoma presence, Level 1. If caught at this level, there is a 95% cure rate.

It can: While melanoma in-situ is Stage O disease, meaning that it has not yet become invasive, if left alone it would become invasive. It is possible that when a nodular melanoma first forms it could be in-situ. However most nodular melanomas are invasive upon diagnosis.