A rare cause of an ileocaecal mass and lymphadenopathy

The presence of a mesenteric mass on imaging, lymphoplasmacytic infiltrate with fibrosclerosis, >30 per high-power field IgG4-positive plasma cells on histology and elevated serum IgG4 supports the diagnosis of IgG4-related mesenteric fibrosclerosis, a manifestation of IgG4-related systemic disease. 1 2 This condition affects middle-aged to older adults, with a male predominance. Determining the degree of fibrosis may be important for predicting steroid response. 1 IgG4-related mesenteric fibrosclerosis may require surgical resection. 4 5 Poor outcome has been demonstrated if the mesenteric lesion encases vital vasculature or extensive resection causes short bowel syndrome.