Phenotypes of encapsulating peritoneal sclerosis--macroscopic appearance, histologic findings, and outcome

Encapsulating peritoneal sclerosis (EPS) is a rare but devastating complication of peritoneal dialysis (PD), with clinical signs of abdominal pain, bowel obstruction, and weight loss in late stages.

We retrospectively analyzed all patients who were diagnosed with EPS between March 1998 and October 2011 in our department of nephrology. We focused on the 24 EPS patients who underwent surgery because of symptomatic late-stage EPS. We identified 3 different macroscopic phenotypes of EPS that we categorized as types I - III. We correlated histologic findings with those macroscopic phenotypes of EPS. The postoperative and long-term outcomes were evaluated by macroscopic phenotype.

Duration of PD was longer in type III than in types I and II EPS (p = 0.05). We observed no other statistically significant differences between the groups in baseline characteristics, except for operation time, which was longer in the type I than in the type III group (p = 0.02). Furthermore, we observed no statistically significant difference between the groups with respect to the onset of complaints before surgery (7.8 ± 5.9 months vs 7.0 ± 7.0 months vs 6.5 ± 5.3 months). Concerning patient outcomes, there was no evidence that any of the macroscopic EPS types was associated with more major or minor complications after surgery. For all study patients, follow-up was at least 3 years, with 19 patients still being alive, and 16 having no or very mild complaints. The typical histologic findings of EPS were present in all macroscopic types; only fibrin deposits were more prominent in type II than in type III.

We describe 3 subtypes of EPS based on macroscopic findings. Postoperative treatment should probably not be influenced by the macroscopic EPS phenotype. Whether the different phenotypes represent different pathophysiologic processes remains unclear and has to be further evaluated.