  We study a two-dimensional Fermi liquid with a Fermi surface containing the
saddle points $(\pi,0)$ and $(0,\pi)$. Including Cooper and Peierls channel
contributions leads to a one-loop renormalization group flow to strong coupling
for short range repulsive interactions. In a certain parameter range the
characteristics of the fixed point, opening of a spin and charge gap and
dominant pairing correlations are similar to those of a 2-leg ladder at
half-filling. An increase of the electron density we argue leads to a
truncation of the Fermi surface with only 4 disconnected arcs remaining.
