  We are concerned with fully nonlinear possibly degenerate elliptic partial
differential equations (PDEs) with superlinear terms with respect to $Du$. We
prove several comparison principles among viscosity solutions which may be
unbounded under some polynomial-type growth conditions. Our main result applies
to PDEs with convex superlinear terms but we also obtain some results in
nonconvex cases. Applications to monotone systems of PDEs are given.
