Into the Mist: A Rare Diagnosis for a Common Symptom

Abstract

Sclerosing mesenteritis (SM) is rare condition involving fibrosis of the small bowel mesentery. The disease course is often benign but can be fatal. It most commonly presents in males with chronic abdominal pain. While the etiology remains unclear, the most common risk factors are history of abdominal surgery, trauma, or autoimmune disorders. SM is suggested by a ‘misty mesentery' sign or soft tissue mass of the mesentery noted on cross-sectional imaging, but diagnosis requires confirmation with mesenteric biopsy. Treatment includes steroids and tamoxifen, and is reserved for those who are symptomatic or have progressive disease. A 57 year old male presented with a decade of left-sided abdominal pain. The pain was initially intermittent in nature, but recently became more persistent. Medical history was remarkable for multiple prior abdominal traumas, and history of malaria infection and heat stroke. Lab workup was only notable for a mild elevation in ESR (25 mm/hr). Physical exam showed a positive Carnett sign; treatment for abdominal wall pain did not improve the patient's symptoms. Abdominal CT scan showed a “misty mesentery” sign surrounding part of the jejunum without a focal mass or pathologic lymphadenopathy. Push enteroscopy and capsule endoscopy were unremarkable. PET scan showed increased activity in the region of the “misty mesentery.” Exploratory laparotomy with biopsy of the mesentery showed fibroadipose tissue with fat necrosis and fibrosis, confirming SM. IgG4 levels were normal. Interval MRI has showed stability of disease extent and the patient has had no evidence of concomitant malignancy or autoimmune disorders. While the patient remained symptomatic, he declined therapy to date due to his concern about the side effects of steroids. This patient had multiple risk factors for SM, including his history of multiple abdominal traumas, malaria, and heat stroke. SM often causes fibrosis that envelops surrounding vasculature and can obstruct other organs including ureters and small intestine making the prognosis range from benign to potentially fatal. Surgical exploration with mesenteric biopsy should be considered for those with cross sectional imaging showing the “misty mesentery” sign in order to make the diagnosis. Our case highlights that SM, while rare, should be in the differential for a patient with chronic abdominal pain and multiple risk factors.