case_images: PMC10757054_01
case_images: Baseline [18F] FDG PET/CT images demonstrating the lymphomatous disease extent (arrows) in conjunction to irrelevant single intraarticular 4 cm hypermetabolic mass lesion occupying the anteromedial aspect of the left knee (asterisk)
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case_images: F1
case_images: Shortly thereafter, initial [18F]FDG PET/CT imaging revealed hypermetabolic lymphomatous disease involving multiple groups of lymph nodes above and below the diaphragm, along with bone, skin, liver, and splenic involvement (Figure 1).
case_images: (a) Initial axial PET/CT image of the left knee revealed hypermetabolic mass occupying the anteromedial aspect of the left knee (arrow). (b) Initial T1 axial MRI of left knee revealed a well-defined intra-articular hypointense soft tissue mass visualized at the medial aspect of the left knee joint space with medial extension lying dorsal to the inferior pole of the patella (arrow). (c) Histopathologic examination of the synovial mass confirmed the presence of giant cell tumor without lymphomatous infiltration
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case_images: PMC10757054_01_AOJNMB-12-57-g002.jpg
case_images: F2
case_images: Interestingly, a suspicious yet irrelevant single intraarticular 4 cm hypermetabolic mass was observed in the anteromedial aspect of the left knee (Figure 2a). Subsequently, MRI of the left knee (Figure 2b) showed a well-defined mass with specific imaging characteristics consistent with a tenosynovial giant cell tumor. A biopsy of the synovial mass was performed to rule out lymphomatous infiltration, confirming the presence of a tenosynovial giant cell tumor without lymphomatous infiltration (Figure 2c). 
case_images: Serial Maximum Intensity Projection images, with their corresponding fused axial PET/CT of the knee (a) performed before chemotherapy, (b) following 3 cycles of chemotherapy (interim), and (c) following the end of therapy demonstrating picture of complete response in Hodgkin Lymphoma but with stable giant cell tumor (arrows)
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case_images: PMC10757054_01_AOJNMB-12-57-g003.jpg
case_images: F3
case_images: HL remission with an otherwise stable giant cell tumor, as depicted by follow-up [18F]FDG PET/CT (Figure 3). His laboratory tests were also unremarkably normal from this timeframe and beyond.