Less common presentation of abdominopelvic lymphoma characterized by peritoneal thickening/nodularity, omental infiltration, ascites, and small bowel thickening. 

The peritoneal and omental disease is more commonly associated with caricinomatosis (such as ovarian) rather than lymphoma, but the soft tissue encasement of the central mesenteric vasculature and long segmental of small bowel thickening without obstruction strongly raise the possibility of lymphoma. 

After creating your differential diagnosis which would appropriately include lymphoma, carcinomatosis, and peritoneal mesothelioma, the next step is to identify the safest targets for biopsy which include US-guided omental, small bowel wall or mesenteric biopsies. Using firm transducer pressure, the small bowel loops were displaced and the rind of soft tissue encasing the central mesentery was biopsied (with great care to avoid vascular injury), confirming the diagnosis of B-cell lymphoma.