Sclerosing mesenteritis mimics gynecologic malignancy.

Sclerosing mesenteritis, inflammatory pseudotumor, retroperitoneal fibrosis and IgG-4 related disease are rare inflammatory conditions that may present as a pelvic mass and mimic malignancy or infection. There is considerable overlap between these inflammatory conditions often leading to diagnostic and therapeutic confusion. Sclerosing mesenteritis is characterized by chronic inflammation, fibrosis and fat necrosis, and is thought to originate from the small bowel mesentery (Akram et al., 2007 May;5). Inflammatory pseudotumors are characterized histologically by myofibroblast-derived spindle cells and lymphoplasmacytic infiltrates. They may affect numerous organs of the body, most notably the orbit and lung, and they are often mistaken for malignancy (Yagmur et al., 2014). Retroperitoneal fibrosis is characterized by fibrosis and inflammation of the retroperitoneum, often causing encasement of retroperitoneal organs including the ureters and aorta (Liu et al., 2014 Nov). IgG 4-related disease is characterized by dense lymphoplasmacytic infiltrate, storiform (irregularly whorled) fibrosis, and obliterative phlebitis (Stone et al., 2012 Feb 9) (Carruthers et al., 2012 Jan). Inflammatory diseases of the retroperitoneum typically occur in men in the sixth to seventh decade of life, occurring twice as often in men than woman. Some hypothesize that risk factors for sclerosing mesenteritis may include autoimmunity, trauma, previous surgery, infectious, and ischemic injury (Akram et al., 2007 May;5). Patients typically present with progressive abdominal and flank pain, abdominal distension, and at times diarrhea, malaise, weight loss, fevers and lower extremity edema. Some patients present acutely with renal failure and hydronephrosis secondary to mass effect and ureteral obstruction (Akram et al., 2007 May;5, Liu et al., 2014 Nov 8). Inflammatory markers such as C-reactive protein and erythrocyte sedimentation rate are often elevated in these patients. An elevated serum IgG-4 level may be helpful in the diagnosis of IgG-4 related disease, although up to 30% of these patients have normal serum levels. Computed tomography scans are the most common imaging study used to aid in diagnosis. Scans may reveal connective tissue around the abdominal ureters, aorta, or show a large mass that broadly occupies the retroperitoneum (Stone et al., 2012 Feb 9). These masses may also show calcifications, retroperitoneal and mesenteric lymphadenopathy, and increased collateral circulation (Liu et al., 2014 Nov). While clinical suspicion and serologic studies may help in diagnosis, histopathological features from a tissue sample remain key to proving a diagnosis. While these conditions can affect almost every organ system, gynecologists will encounter them when a patient presents with a retroperitoneal pelvic mass. These masses are often unresectable, but as their etiology is thought to be immune-mediated, they tend to respond well to immunosuppressive therapy.