What is the difference between a severely atypical mole and melanoma?

The difference is...: That atypia in a mole (or nevus) is generally thought to represent a premalignant change but not an invasive malignancy. A melanoma is a malignant tumor that can invade surrounding tissue and metastasize (spread) to other organs and lymph nodes. The difference is premalignant vs. Malignant.

One is cancer : Ant atypical mole displays abnormal cell behavior that may be indicative of a premalignant lesion whereas melanoma is a cancer. While melanoma requires urgent treatment, an atypical mole requires attention as well. This should prompt a full body evaluation for other suspicious lesions as well as lifelong surveillance examination and self exams.

Spectrum: Severely atypical mole is considered a premalignant condition. It is not defined as cancer and does not have an invasive component yet. Melanoma is cancer has can develop the ability to travel throughout the body.