Symptoms and imaging. People usually present with symptoms -- eg, fever, chills, night sweats, fatigue, lymph node enlargement, spleen enlargement, etc. Then (or sometimes incidentally) abnormal lymph nodes are noted on ct scans. A biopsy (of lymph nodes and/or bone marrow) is needed for diagnosis. Less often blood abnormalities show a leukemic (blood) component of lymphoma or other abnormalities.
Imaging and biopsy. Usually the doctor suspects a major illness based on clinical symptoms: fever, weight loss, night sweats, fatigue...Eventually ct scans are done and this shows evidence of enlarged lymph nodes or possible masses. A biopsy has to be done to truly diagnose lymphoma. To finish out staging the disease, the doctor may also require a pet/ct, other blood tests and a bone marrow aspirate and biopsy.