The shape of two-dimensional liquid expanded droplets of a methyl octadecanoate Langmuir monolayer confined in gas cavities in a liquid condensed matrix is studied using fluorescence microscopy. Confinement destabilizes the circular shape by increasing the dipole density of the liquid expanded phase or by decreasing the bare line tension A between the liquid expanded and the gaseous phase. Confinement causes a cascade of shape transitions from a circular droplet toward shapes of n-fold symmetry with increasing n until the droplet returns to a circle as its size approaches the size of the cavity. The experiments are explained theoretically, and it is shown that the three phase coexistence region is not an equilibrium phase coexistence region. Material parameters depend on the relative area fraction of the coexisting phases.