Incidental finding on ct of enlarged mesenteric lymph nodes only one at 1cm. does it make sense to wait 90 days to repeat ct. ?

Yes: A size of 1cm is not significantly enlarged; lymph nodes act as filters so tend to enlarge when they filter things from the blood, such as bacteria causing infection. It is reasonable to repeat imaging in 6 weeks to see if the lymph nodes are enlarging or getting smaller. If they are decreasing in size there is no reason for concern

Ans: Yes it does. You are vague with the results of the test. But it here can be inflammation of lymph nodes for many reasons. Need more thorough he as to what led up to the cr scan. Was your blood work abnormal?

Yes, usually: An incidental finding is one that is not expected based on clinical history and examination findings; i.e., there was no evidence for infection or tumor in that area. So, first order is to see if it is biologically active growing, or shrinking. If growing, "What? and why?" =>careful review of earlier illnesses, more detailed imaging, labs; etc If not, watchful waiting is OK.

Yes...: The finding is nonspecific. This could be a reactive node from an inflammatory or infectious process. Clinical correlation may be helpful to determine the frequency of follow-up. Are you having symptoms? Do you have any medical history pertinent to this finding?