A display case has a first display case portion with walls configured so that each wall of a plurality of first fixed walls has a coupling edge arranged at the same coupling framework between the first portion and a second portion of the display case. The coupling edges of the first fixed walls are coplanar to one another and at least two of the first fixed walls are adjacent to each other and fastened together through gluing along a corner substantially perpendicular to the plane of the coupling edges. A groove is formed longitudinally on the coupling edge of each of the first fixed walls, the grooves of the first fixed walls jointly defining a channel along the coupling framework; a hoop cable is housed in the channel, closed on itself.The hoop cable contributes to keeping the walls coupled together at the coupling framework, ensuring that the walls stay in position even in the case in which the gluing with which the first fixed walls are fastened together partially or even totally gives way.