  Radially symmetric shadow wave solutions to the system of multidimensional
pressureless gas dynamics are introduced, which allow one to capture
concentration of mass. The transformation to a one-dimensional system with
source terms is performed and physically meaningful boundary conditions at the
origin are determined. Entropy conditions are derived and applied to single out
physical (nonnegative mass) and dissipative (entropic) solutions. A complete
solution to the pseudo-Riemann problem with initial data exhibiting a single
shock on a sphere is obtained.
