Tissue ablation probes and methods of treating diseased tissue are disclosed that include or use a partially uninsulated shaft that carries conductive elements such as electrode arrays. The shaft has an uninsulated outer surface that is electrically conductive and is electrically connected to one of the conductive elements. The uninsulated outer surface and one of the conductive elements are insulated from the other conductive element. Tissue ablation is performed “inside-out” and begins between the proximal and distal electrode arrays and migrates outwardly towards the electrode arrays when electrical current is applied to the probe.
