Tuberculosis-Associated Hemophagocytic Syndrome Mimicking Malignant Lymphoma: A Case Report.

A 78-year-old man presented with prolonged fever, weight loss, erythema, and necrotic lymphadenopathy. Initial suspicion of malignant lymphoma-associated hemophagocytic syndrome (HPS) arose from high Fluorodeoxyglucose (FDG) uptake in lymph nodes on PET/CT. However, lymph node biopsy revealed caseous necrosis and granulomas containing acid-fast bacilli, confirming tuberculosis-associated HPS. Diagnosis was delayed due to a negative interferon-gamma release assay and imaging and clinical features resembling malignancy. This case demonstrates that tuberculosis can act as a great mimicker, often presenting similarly to malignancy and complicating diagnosis. Necrotic lymphadenopathy with peripheral enhancement on CT and overlapping Maximum Standardized Uptake Value (SUVmax) values on PET/CT should raise suspicion for tuberculosis in similar cases. Early lymph node biopsy is essential for differentiating tuberculosis from malignancy, ensuring appropriate treatment. Although anti-tuberculosis therapy combined with corticosteroids improved systemic inflammation, the patient's frailty worsened. This case highlights the importance of considering tuberculosis in the differential diagnosis of systemic inflammation with cytopenia and lymphadenopathy to improve outcomes in severe conditions.