Can malignant melanoma be found inside the body?

Metastatic: Metastatic melanoma can be found in other organ like brain, lung and liver. This means the melanoma has spread from the skin to other organ systems.

Yes, but...: ..In that case it would be a metastatic deposit, originally from a melanoma somewhere on the skin.

Yes: Surprisingly, these can and sometimes do pop up in places that have never been sun-exposed. Famously this can happen within the deep vulva and the esophagus.

Yes: Melanoma can travel to any organ in the body.