Clinical Presentation

A 23-year-old man presents with right lower quadrant pain and fever.

(A) Contrast-enhanced computed tomography (CT) of the pelvis with oral contrast shows a cluster of enlarged mesenteric lymph nodes (arrow) in the right lower quadrant, adjacent to the cecum. The appendix fills with contrast (arrowhead). There is no cecal or appendiceal wall thickening or mesenteric fat stranding. (B) More caudal image shows contrast filling the appendix (arrowhead ) without dilatation, mural thickening, or pericecal inflammatory changes.

Differential Diagnosis

• Mesenteric adenitis: This is the most likely diagnosis for a cluster of lymph nodes in the right lower quadrant without other evidence of inflammation or neoplasm.