A diagnostic device (10) for pathologies of tubular anatomical structures comprises a tubular elongated structure (12, 28) developing between a proximal end and a distal end and is suitable to be inserted in the tubular anatomical structure, means (22, 32) for locally dilating the walls of the tubular anatomical structure that are associated with the distal end of said elongated structure, said means for locally dilating being movable between a closed position for introducing the device and at least one open position for viewing and evaluating the pathology, and control means being associatedwith the proximal end of the elongated structure, said control means being operatively connected to said means for locally dilating, in order to move them between the closed position and the open position, and vice versa.