Can Artifact Mimic the Pathology of the Peritoneal Mesothelium?

Abstract

Objective A peritoneal biopsy registry was established to examine morphological and functional changes to the peritoneum during peritoneal dialysis (PD). During the early stages of this study, it became clear that surgical trauma to the peritoneum at the time of biopsy could cause a variety of changes to the surface. We examined the effects of surgical trauma in a rat biopsy model. Design Rat peritoneum was subjected to a variety of traumas that might occur at biopsy and compared with peritoneal biopsies that had been collected, using the suture method described here, from PD patients. Changes in the quality of non-PD biopsies taken before and after the development of the suture technique were evaluated. Results In the rat model, external massaging of the peritoneum induced moderate loss of microvilli. Brief light touching caused distortion of the mesothelial surface. Pressing resulted in mesothelial denudation and thin strands of presumed cellular remains. Rubbing caused complete loss of mesothelial cells and their basement membrane. Air drying caused progressive loss of microvilli and eventual cellular distortion. Comparison with peritoneal biopsies from PD patients revealed similarities with certain types of trauma, namely, air drying and pressing. Collection of peritoneal biopsies using the suture method significantly improved specimen quality compared with specimens taken before its introduction ( p < 0.025%). Conclusion These results illustrate the sensitivity of the mesothelium to mechanical trauma, the possibility of confusing trauma with genuine pathology, and, hence, the necessity of employing a trauma-free method of biopsy collection, such as the technique described here.

Proposal of peritoneal biopsy procedures for patients undergoing peritoneal dialysis

“…Evaluation of the peritoneal morphology becomes difficult if the peritoneal sample comes in direct contact with the peritoneal surface or electrocautery or is excessively stretched at fixation. In a previous study, von Ruhland et al [7] conducted a simulation of various types of surgical trauma to the rat peritoneum. The authors demonstrated that peritoneal mesothelial cells could undergo degeneration simply following exposure to ambient air or massage of the peritoneum; furthermore, this change resembled the peritoneal surface sampled from a patient undergoing PD.…”

“…(3) The peritoneum is sampled without direct contact and electrocautery to avoid mechanical injury. (4) The specimen is placed on cellophane without excessive stretching so In an earlier report, it has been shown that the specimen should be pinned onto a corkboard, with the mesothelial surface being on the top, after being briefly placed in sample buffer [7]. However, in our experience, the actual evaluation of the specimen is difficult because of its forcible fixation.…”

“…To the best of our knowledge, only a few studies have reported on the methodology of peritoneal biopsy [7][8][9][10]. Moreover, a detailed biopsy procedure has been described in only one study [7], where the authors have proposed a suture method for collecting peritoneal samples. Briefly, a suture is inserted into the outer part of the abdominal musculature, and the area is raised to avoid any accidental damage to the underlying organs.…”

“…At our hospital, peritoneal biopsy examinations are performed not only after the cessation of PD but also before the initiation of PD to evaluate the serial morphological changes induced by PD in the peritoneum. A unified method for performing peritoneal biopsy remains to be established because, to date, few studies have reported on its methodology [7][8][9]. Therefore, the technique for a peritoneal biopsy varies across institutions.…”

“…Therefore, the technique for a peritoneal biopsy varies across institutions. Reportedly, an accurate evaluation is complicated by the absence of an appropriate sampling technique, especially in cases with a peritoneum of almost normal thickness, which is prone to mechanical damages [7]. The thickness of the peritoneum prior to performing PD is around 100 μm; however, the degree of thickness becomes remarkable with the prolongation of PD.…”