CTshows Spleen 17cm, small Axillary Lymph nodes, retroperitoneal lymph nodes& mesentric lymph node noted, normal blood count &bone marrow, no infection?

Many possibilities. The combination of enlarged spleen and internal lymph nodes could be any of several infections (mononucleosis, syphilis, HIV, and several others, of course depeding on risk); inflammatory conditions like sarcoidosis; various malignancies like lymphoma and others. The doctor(s) who have been evaluating this problem and requested the CT scan are the only ones who can answer accurately. Good luck.