IgG4-related sclerosing mesenteritis is one of the IgG4-associated inflammatory disorders.
Clinical presentations:
(1) abdominal pain
(2) weight loss
(3) bowel obstruction
Imaging studies show a solitary mass at the root of the small bowel mesentery. The mass may show heterogeneous F-FDG avidity.
Laboratory testing shows:
(1) elevated serum IgG4 concentration
(2) elevated C-reactive protein
Grossly a hard mass is present in the mesentery.
Histology shows:
(1) marked sclerosing fibrosis with a storiform pattern
(2) obstructive phlebitis
(3) follicular hyperplasia
(4) a plasma cell infiltrate
(5) elevated number of plasma cells staining for IgG4 (> 60 per high power field; ratio of IgG4 positive to IgG positive cells > 40%).
The mass usual responds to long-term low-dose steroid therapy,
