Abstract: A tissue specimen stage is provided having a window with surface curvature upon which an excised tissue specimen is locatable, a carriage having a tissue specimen receptacle to which the window is mounted, and a platform supporting the carriage and presenting the window to the objective lens of an optical sectioning microscope. The carriage is mounted to the platform for movement along two rotational axes so that the carriage's movement follows the curvature of all or part of the window while maintaining the same optical geometry of the window with respect to the objective lens. The window has surface curvature adapted to at least approximate the shape or curvature of the non-histologically prepared tissue specimen to be placed thereupon.