Persistent ¹⁸F-FDG Uptake in a Post-treatment Hodgkin's Lymphoma: Not Always Residual Disease

We report the case of a 31-year-old woman with osseous Hodgkin's lymphoma who underwent post-therapeutic ¹⁸F-fluorodeoxyglucose (¹⁸F-FDG) positron emission tomography/computed tomography. The scan revealed a hypermetabolic lesion in the pubic symphysis and iliac crests, initially suggestive of residual disease. Multimodal evaluation, including ^99mTc-methoxy-isobutyl-isonitrile scintigraphy, laboratory tests revealed primary hyperparathyroidism, and biopsy confirmed a brown tumor. This case highlights the importance of integrating multimodal imaging and pathology to avoid misinterpretation of ¹⁸F-FDG-avid lesions.