Patient: Male, 80Final Diagnosis: Sclerosing mesenteritisSymptoms: Abdominal distension • abdominal tendernessMedication: —Clinical Procedure: ParacentesisSpecialty: Gastroenterology and HepatologyObjective:Rare diseaseBackground:Sclerosing mesenteritis (SM) is a rare idiopathic inflammation and fibrosis of the mesentery. Its etiology and pathogenesis remain unclear. It has been linked to abdominal trauma related to peritoneal dialysis, recent abdominal surgery, idiopathic inflammatory disorder, paraneoplastic syndrome, ischemia/infection, and autoimmunity. Abdominal CT is the most sensitive imaging modality, and diagnosis is usually confirmed by surgical biopsy. Patients most often present with abdominal pain, nausea, vomiting, diarrhea, and weight loss, and less commonly with chylous ascites and small bowel obstruction. Treatment is usually supportive; surgical intervention may be attempted for life-threatening complications such as bowel obstruction or perforation.Case Report:This report describes an 80-year-old man with hypertension and end-stage renal disease (ESRD) presenting with increasing abdominal pain and tenderness over the past 5 months. Abdominal enhanced computed tomography (CT) revealed a fat-ring sign and peritoneal calcifications along the serosa surface of small bowel consistent with sclerosing mesenteritis. His hospital course was complicated by increasing ascites requiring multiple ultrasound-guided paracentesis, worsening leukocytosis, and persistent hypotension after dialysis, requiring pressor support. Ascitic fluid analysis was consistent with chylous ascites. The patient subsequently developed small bowel obstruction causing focal perforation, leading to the death of our patient. In this report, we review the clinical presentation, radiographic findings, treatment, and outcome in our patient and review the relevant literature.Conclusions:Diagnosis of sclerosing mesenteritis is challenging due to its nonspecific clinical features. Sclerosing mesenteritis is a debilitating albeit self-limiting disorder that can rarely become fulminant, largely due to its complications.