In this article, we present a continuous model for tumor growth . This model describes the evolution of three cellular densities: the density of sane tissue, cancer cells and extracellular medium. In order to render correctly the cellular division, this model use a discrete description of the cell cycle (the set of steps a cell has to undergo in order to divide) presented in [7]. To render cellular adhesion and the mechanics which may influence the growth, we use a viscoelastic approach. This model extends the one presented in [7] with a more realistic description of the movement.