  For the first time the phenomenon of cellular structure coarsening are
consistently analysed from the positions of kinetic, hydrodynamic and
stochastodynamic theories of nonequilibrium statistical systems. Thereby
micro-, meso- and macroscopic levels of approach are distinguished. At the
microscopic level the cellular structure is describe by a probability
distribution function in a phase space of cell coordinates and of cell sizes. A
kinetic equation for the function is written and a development to a
hydrodynamic equation of a mesoscopic cell medium is realised. It has the form
of a diffusion-reaction equation with a negative "diffusion" coefficient and
with a cell interface density playing the role of concentration. Its analysis
reveals a new effect of macroscopic patterning in the cell medium: existence of
space-correlated stochastic fluctuations of the cell interface density.
