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.