A Case Report: Systemic Lymph Node Tuberculosis Mimicking Lymphoma on 18F-FDG PET/CT.

18F-fluorodeoxyglucose positron emission tomography—an established modality for evaluating malignancies—exhibits increased uptake under inflammatory conditions. A 21-year-old man came to our hospital with persistent pain in his right lower quadrant of abdomen for more than 1 month, but had no diarrhea, fever, chills, weight loss, or other constitutional symptoms. Colonoscopy analysis showed no organic diseases in his colorectum. Ultrasound results revealed multiple enlarged lymph nodes in the bilateral neck, axilla, and groin. Positron emission tomography analysis was performed and showed intense 18F-fluorodeoxyglucose accumulation in the bilateral neck, supraclavicular, pulmonary hilar, mediastinum, gastric paracardial, and mesenterium lymph node. These findings were considered typical for lymphoma. To confirm the diagnosis, we obtained a diagnostic biopsy in the left supraclavicular lymph node. The diagnosis of tuberculosis was confirmed in the final pathology. This uncommon case underscores the necessity of considering lymph node tuberculosis as a possible differential diagnosis in lymphoma.