Tissue expander system including a tissue expander, an injection port, and a tube connecting the tissue expander to the injection port. The tissue expander is of a one piece molded body of a pancake to waffle like configuration. Within the one piece molded body is a member of non-stick material of a slightly smaller geometrical shape similar to that of the one piece molded body. A self-sealing valve member closes off the tube in the tissue expander after injection of a solution for expanding the tissue expander. A Dacron mesh can be embedded in members of the one piece body providing for directional expansion of the tissue expander. In an alternative embodiment, Dacron mesh can be provided in both the upper and lower members of the one piece body. An accordion configured perimeter also provides for upward directional expansion. The tissue expanders can assume any geometrical configuration, whether it be square, rectangular, circular, oval, or kidney shaped. The tissue expander can also be a small enough size for hands and toes, a miniature size for use on the face, or a large size for use on the chest or other body area. A self-sealing injection port can be domed or cylindrical, and includes a stainless steel bottom, as well as a Dacron mesh impregnated silicone top. The stainless steel bottom provides for limiting injection needle penetration and for injection port location during X-ray procedure.