Idiopathic Sclerosing Mesenteritis: Uncommon Cause of Abdominal Pain

Abstract

Purpose: Idiopathic sclerosing mesenteritis is a disease of the small intestine, characterized by chronic inflammation and eventual fibrosis of the mesentery. Methods: A 79-year-old female was admitted for recurrent episodic dizziness, nausea with vomiting and abdominal pain. The patient was treated for vertigo six weeks ago in the ER and had head CT, which was essentially normal. She had been feeling fine between episodes. PMHx was significant for hypothyroid and hypertension. No prior history of surgery or trauma to the abdomen. The patient was on lisinopril and synthroid. Initial labs were unremarkable. CT abdomen showed a prominently calcified mass in mesentery, with tethering of small bowel loops. Twenty-four-hour urine for 5-HIAA for carcinoid syndrome, ESR and CRP were normal. Upper endoscopy and colonoscopy were unremarkable. Gynecologic evaluation was unremarkable. Results: Patient went for laparoscopic segmental resection of 11.5 cm of small bowel and mass to exclude malignancy. Pathology showed a segment of unremarkable small bowel and attached mesentery. Within the mesentery, there was an ill-defined area characterized by patchy mild chronic inflammation, numerous foamy histiocytes and broad, irregular bands of sclerosing collagenous tissue. Marked dystrophic calcification was present as well. The histologic features were those of sclerosing mesenteritis. Immunohistochemistry staining for IgG4, cytokeratin and B-cell lymphoma, including SLL and mantle cell lymphoma, were negative. Conclusion: The epidemiology is unknown, as the disease is rare. Most reports have found a male preponderance. Pathogenesis includes previous abdominal surgery or trauma, autoimmunity, paraneoplastic syndrome, ischemic injury and infection. The most common clinical presenting symptom is abdominal pain, but 50% of patients can have an abdominal mass typically in the left upper quadrant or epigastrium. The erythrocyte sedimentation rate and C-reactive protein level may be elevated and serve as surrogate markers of a therapeutic response to medical therapy. Abdominal imaging is an essential component of the diagnostic evaluation, but the diagnosis is established by histologic evaluation. In patients who are symptomatic, tamoxifen, azathioprine or cyclophosphamide may be used for stabilization of symptoms, and thalidomide can be considered for refractory cases. Surgery is best reserved for obstructive complications and to exclude malignancy.