This patient had a several-month history of abdominal pain including a recent surgery with small bowel resection (pathology not available). The ESR was significantly elevated indicating an inflammatory etiology (without elevated WBC), and the patient rapidly improved following a course of IV dexamethasone, indicating responsiveness to steroids.

Based on the diffuse involvement of the entire GI tract (multiple vascular territories with stomach, small bowel, and large bowel) and genitourinary tract, a systemic process such as vasculitis was favored to be the most likely diagnosis. In this age group, lupus vasculitis would be a primary consideration and has more commonly been described with similar imaging manifestations. Eosinophilic gastroenteritis was another consideration, but this patient did not have a supporting clinical picture and that would not account for the bladder abnormalities. 

The enhancing bladder nodules and hydroureteronephrosis are unusual findings, and without the underlying GI inflammation, a primary consideration might be endometriosis. However, there is actually a strong association with genitourinary/bladder involvement with lupus vasculitis, which is associated with UVJ inflammation/contraction causing hydronephrosis (seen in this case) and cystitis, supporting it as the most likely diagnosis.