Sclerosing Mesenteritis Mimicking IgG4-related Disease

A 72-year-old man was followed as an outpatient at our hospital for 6 years after surgery for small cell carcinoma of left adrenal gland origin. Follow-up abdominal computed tomography showed a 6-cm mass in the left lower mesentery. The patient underwent open laparotomy. The histological diagnosis was sclerosing mesenteritis. The previous specimens of the left adrenal mass were then re-examined with a microscope, and panniculitis was found around the small cell carcinoma. Both lesions were histologically similar to IgG4-related disease (RD), but they did not completely meet the diagnostic criteria of IgG4-RD clinically or histologically.

[Immunoglobulin G4 Unrelated Idiopathic Mesenteric Sclerosis]

Sclerosing mesenteritis is a rare benign disease with a prevalence of 0.16-3.4% and is characterized by chronic nonspecific inflammation and extensive fibrosis in the adipose tissue of the mesentery although the exact pathogenesis is still elusive. A 65-year-old woman was referred with suspicion of an abdominal mass and biliary stones on abdominal ultrasonography and CT. Bile duct stones were confirmed by endoscopic ultrasonography and successfully treated by endoscopic retrograde cholangiography with stone removal. Furthermore, a 4.7 cm conglomerated mass on small intestinal mesentery was suspected as sclerosing mesenteritis based on the features on abdominal MRI. However, because it could not be differentiated from malignancy without histologic examination, laparoscopic excisional biopsy was performed; it showed only inflammatory cells with extensive fibrosis. Therefore, the abdominal mass was confirmed as sclerosing fibrosis and the patient was followed-up without any treatments because no mass-related symptoms accompanied the findings. Six months later, abdominal CT showed no significant change in the mass. Herein, we report a rare case of incidentally found idiopathic sclerosing mesenteritis.

[A case of IgG4-related sclerosing mesenteritis associated with Crohn's disease]

Sclerosing mesenteritis (SM) is a rare disease characterized by chronic nonspecific mesenteric inflammation and fibrosis of unknown etiology. Some tumefactive SM shows diffuse accumulation of IgG4-positive plasma cells and is considered as a part of the spectrum of IgG4-related disease. An association between inflammatory bowel disease and IgG4-related disease has been indicated. A 45-year-old woman visited our hospital due to weight loss with intermittent lower abdominal discomfort. Pelvic ultrasound revealed a mass-like lesion in the abdominal wall and pelvis MRI demonstrated a 5.9 cm sized wall-enhancing mass with heterogeneous signal intensity from right adnexa to the abdominal wall. Tumor resection and adhesiolysis was done because of severe adhesion with the small bowel, colon, bladder, uterus, and abdominal wall. Appendectomy was also performed due to adhesion and edematous change. Histological examination of the resected mass showed findings that were compatible with IgG4-related SM. The resected appendix showed chronic granulomatous inflammation without evidence of tuberculosis. She was diagnosed with Crohn's disease after undergoing colonoscopy and CT enterography. Herein, we report a rare case of IgG4-related SM that occurred in conjunction with Crohn's disease.