What is "microscopic ulceration" and why is it important in diagnosing skin cancer?

What is "microscopic ulceration" and why is it important in diagnosing skin cancer?

When the biopsy is done of a malignant melanoma, one of the things that is looked at is the nature of the cells; the cells as they invade in the epidermis down into the dermis, as well as whether or not the epidermis is ulcerated. When the epidermis is ulcerated, the lesion, despite all other factors, is considered a more likely lesion for metastasis and is clicked up a half notch in the staging. Ulceration is considered a sign of some aggressiveness and will mirror a greater possibility of metastasis.