[Perforations in Crohn's ileitis and their consequences in the natural history of the disease].

Not all Crohn's ileitis perforations occur in the peritoneal cavity; a proportion of them, which may be theoretically calculated as about 8%, occurs between the two leaves of the mesentery. These mesenteric perforations (which perhaps may be called more properly "penetrations") produce their pathological consequences in three consecutive anatomical compartments: 1) between the two leaves of the mesentery, causing mesenteric abscesses which are very dangerous, especially because of their embolisation into portal vessels (pylephlebitis, hepatic abscesses); 2) in the lower right quadrant of the retroperitoneum, causing what we call "Mesenteric Insertion Retroperitoneal Syndrome" (MIRS), consisting of a collection producing genito-femoral neuralgia, psoitis, obstructive uropathy and iliofemoral thrombophlebitis; 3) out from the pelvis, causing collections which in their spreading recall the cold abscesses of Pott's disease and which, diffusing along muscles and nerves, reach Scarpa's triangle, or the buttock and popliteal space.