Rippled mesh: a CT sign of abdominal wall ePTFE prosthesis infection.

BACKGROUND Infection of polytetrafluoroethylene (ePTFE) prostheses for abdominal incisional hernia is a rare but serious complication that often makes meshes removal necessary. Instead serous collections (seromas) without signs of infection don't require surgical removal. Differential diagnosis between infected and non-infected fluid collections is difficult and sometimes impossible before surgical exploration. METHODS We describe a new sign observed in two patients who underwent abdominal computed tomography for evaluation of a fluid collection without clear signs of prosthesis infection, complicating abdominal wall repair for incisional hernia in which an ePTFE mesh was used. In both patients an alteration of the mesh profile was demonstrated on imaging, and in both patients prostheses resulted infected at surgical exploration and at microbiological examination after removal. The sign we observed is not evident in computed tomography images performed in cases of seromas. CONCLUSIONS We discuss the possible mechanism of this finding and propose that this sign may be due to a "rejection" of the infected prosthesis from the surrounding neo-formed fibrous and inflammatory tissue.