Abstract: The present disclosure relates to a piston diaphragm seal for transmitting a pressure of a medium to a pressure-measuring sensor a base body having a recess and a bore which is connected to the recess. The recess and the bore can be filled with a pressure transfer medium. A piston is arranged in the recess and can be moved within a predetermined region in the recess. A surface of the piston facing the medium can be loaded with the pressure of the medium, wherein the piston is separated by at least two sealing elements from the medium and the pressure transfer medium. A cavity is arranged in the piston between the at least two sealing elements. An attachment region is provided for connecting the piston diaphragm seal to the pressure-measuring sensor. A monitoring unit is designed to determine and/or monitor entry of medium and/or pressure transfer medium into the cavity.