A 28-year-old Caucasian male with end-stage-renal-disease due to juvenile nephronophthisis developed a severe form of calcifying EPS approximately 10 years ago. His medical history included the presence of hypertension and mitral valve prolapsing without significant regurgitation. The patient was started on continuous ambulatory PD therapy at the age of 13 years and his initial PD regimen included 4 dwells of dialysate glucose solutions 1.36% with fill volume 2 L. Since the peritoneal equilibrium tests showed persistently a high transport status (dialysate-to-peritoneal creatinine ratio: 0.78), 2 years later the patient was switched to continuous cyclic PD with 4 night-time dwells of dialysate glucose solutions 1.36% (duration: 8 h; cycles: 4; fill volume: 2 L) and a daytime dwell with icodextrin (fill volume: 1.5 L). The patient followed a typical clinical course characterized by adequately delivered dialysis and sufficient peritoneal ultrafiltration of ~ 1.5 L/day with a progressive intensification of his PD regimen (continuous cyclic PD with 4 nighttime dwells of dialysate glucose solutions 2.36% and a daytime dwell with icodextrin) till the age of 19 years. Over this period, the patient had secondary hyperparathyroidism and received therapy with calcium-containing phosphate binders and active vitamin D analogs because the patient could not tolerate oral administration of cinacalcet due to gastro-intestinal side effects. The only PD-related complications were 3 episodes of peritonitis due to Staph. Epidermidis successfully treated with intraperitoneal antibiotics. After 6 years on automated PD, the patient developed a progressive reduction in peritoneal ultrafiltration that necessitated the intensification of the PD regimen. In parallel, the patient reported symptoms of atypical abdominal pain, anorexia, vomiting and constipation, raising the clinical suspicion of EPS. A computed-tomography (CT) scan in November 2009 showed a calcified fibrous cocoon wrapped around the bowel, extensive peritoneal thickening and intra-abdominal adhesions of calcified intestinal loops, confirming the diagnosis of calcifying EPS. The initial therapeutic approach included the removal of the peritoneal catheter, transfer of the patient to hemodialysis and administration of corticosteroids (prednisone at a dose of 40 mg/day) in combination with tamoxifen 20 mg/day. The clinical course of the patient over the subsequent 3 months was dramatic due to severe symptoms of total bowel obstruction (ileus stage), malnutrition and rapid weight loss of 20 kg that mandated the prolonged in-hospital treatment and nutritional support with parenteral supplements (1 lt Oliclinomel N4/24-h during the first month and 1lt Oliclinomel N4 3 times per week during dialysis thereafter till the patient was given discharge from the hospital). Despite the severe initial clinical presentation, the patient followed a satisfactory clinical course over the next 6 months with remission of gastrointestinal complications and progressive improvement in his nutritional status. Despite the clinical improvement, repeated CT scans showed the persistence of peritoneal thickening and intra-abdominal calcifications with modest improvement in radiological picture over time. In this context, prednisone was gradually tapered over 6 months to 10 mg/day and was permanently discontinued after 18 months of therapy. Tamoxifen remained unmodified and was administered at a low-dose of 20 mg/day over a 10-year-long period. Long-term therapy with tamoxifen was well-tolerated and was not accompanied by any thrombo-embolic complications or other drug-related adverse effects. During follow-up, the patient experienced minimal gastrointestinal complications, maintained a stable nutritional status and required only 7 short-term hospitalizations due to episodes of incomplete bowel obstruction. All these episodes were mild and were successfully managed with conservative treatment (i.e., gastro-intestinal rest, antibiotics, etch). Immediate surgical treatment, corticosteroids or parenteric nutritional support was never required during follow-up. As shown in Table, the management of secondary hyperparathyroidism over this period was based on low-to-moderate doses of intravenously administered paricalcitol as well as on optimal oral treatment with phosphate-binders.