A guidable cutting instrument for cutting a tissue specimen from a tissue mass comprises a cannula having a curve formed along a distal portion thereof, and a stylet having a specimen-receiving notch and a curve formed along a distal portion thereof. The stylet is received in the cannula, and is axially extendable therefrom such that the notch is capable of penetrating the tissue mass. The cannula is axially movable over the extended stylet for severing the specimen from the mass for capture in the notch. The cannula and stylet are each structured and arranged for relative rotation between a first position wherein the cannula curve and the stylet curve are in phase to define a curved condition for a length of the cutting instrument, and a second position wherein the cannula curve or stylet curve is rotated relative to the other curve in a manner to define a generally linear condition of the cutting instrument. The selective relative curvature allows the cutting instrument to be steered around obstructions encountered in the body under real time visualization.
