A biopsy on my mole came back moderately atypical Nevus. Is it necessary to have an excision done on it?

You are correct, the research is inconclusive.  It often depends on your dermatologic surgeon's preference and comfort level.  Some are comfortable watching and waiting, while others are less risk-tolerant and prefer to excise.  Generally speaking, it would be ok to watch and observe, as long as you have more frequent skin checks - I would recommend at least every 6 months for a couple of years if you do not have excision (again, there are no formal guidelines for frequency of skin checks).  If you have a history of several atypical moles, definitely use your sunscreen and perform skin self-exams as well!

Many skin pathologists (dermatopathologists) classify
atypical moles or dysplastic nevi as having mild, moderate, or severe
atypia. Unfortunately this
classification system is very subjective and pathologists looking at the same
specimen will often disagree on the level of atypia.

One approach is to not use this confusing language and to
call all of these lesions “Clark’s nevi.”

So, to answer your question:
An atypical mole with moderate atypia is not melanoma. It does not mean that mole is
“pre-melanoma.” You may not have to have
it re-excised.

We do not remove these moles further and we
tell the patient that the mole is benign.

We do worry if the report says a dysplastic nevus has
“severe atypia” or if the report says that the mole is a “Clark’s nevus with
unusual features.” In both cases, the
pathologist should explain what those worrisome features are and whether or not
he/she thinks the lesion is an early evolving melanoma.

An article in the Journal of the American Academy of
Dermatology in 2010 suggested that dysplastic nevi with mild or moderate atypia
may not need to be removed.