You Do Need power plug adapter while traveling from Lithuania to American Samoa.

Here is Why You Need An Adapter

The outlet and plug type used in American Samoa are A, B, F and I and in Lithuania are C and F. This is how they look like.

Lithuania

In Lithuania, outlets of type C and F are in use.

Type C

Type F

American Samoa

In American Samoa, outlets of type A, B, F and I are in use.

Type A

Type B

Type F

Type I