Enlarged lymphnode anywhere in the body may indicate inflammatory/infective/neoplastic etiology and it is very difficult to say what your daughter may have. The best answer would only come after further imaging and biopsy of the node, which will give us the exact diagnosis in your case.
CT scan of abdomen is usually done with oral contrast and i/v contrast and using both is essential to comment on lymphandenopathy. It is difficult to differentiate lymphnodes from unopacified bowel loops.