The main result of this paper
shows that if R is a prime ring with involution and with derivation D, then if
p(x,y) = c1xyD+ c2xDy + c3yxD+ c4yDx is central for all (skew-) symmetric
elements of R, then R must embed in M2(F), with two explicit exceptions. As a
consequence of the special case when x = y, one obtains generalizations of
existing results about (skew-) centralizing derivations of the (skew-) symmetric
elements.