Contrary to the Yamabe case, metrics of prescribed Q-curvature in dimension 4 and higher, can blow-up both on isolated points and on higher dimensional submanifolds, as discovered by Adimurthi, F. Robert and M. Struwe. We will show, in a radially symmetric situation, that both kind of blow-up behaviour can happen at the same time.

This is based on a joint work with A. Hyder.