Pigmented villonodular synovitis mimics metastases on fluorine 18 fluorodeoxyglucose position emission tomography-computed tomography

Abstract

Pigmented villonodular synovitis (PVNS) is a benign joint disease best characterized on magnetic resonance imaging (MRI). The role of fluorine 18 fluorodeoxyglucose ( 18 F-FDG) position emission tomography-computed tomography (PET-CT) in the diagnosis or characterization remains unclear. PVNS displays as a focal FDG avid lesion, which can masquerade as a metastatic lesion, on PET-CET. We present a case of PVNS found on surveillance imaging of a lymphoma patient.

Pigmented villonodular synovitis: A close mimic of metastasis on 18F-fluorodeoxyglucose positron emission tomography/computed tomography

“…PVNS presents as FDG avid mass and thus is a potential mimic for metastatic disease in a known case of cancer. [ 2 3 4 5 ] As seen in our case, it detected intensely FDG avid soft tissue around the hip joint-an index symptom site however it turned out to be PVNS on HPR correlation rather than metastatic disease. Microscopically, these lesions are characterized by the pigment-laden foamy macrophages and giant cells.…”

Acute Findings on FDG PET/CT: Key Imaging Features and How to Differentiate Them from Malignancy

“…However, an isolated FDG-avid lesion can be due to both benign and malignant etiologies. For example, case report that pigmented villonodular synovitis and solid aneurysmal bone cyst can demonstrate increased FDG uptake and mimic malignancy [ 64 , 65 ]. In these situations, MRI would be helpful to differentiate.…”

Histologically benign metastasizing tenosynovial giant cell tumor mimicking metastatic malignancy: A case report and review of literature

“…The differential diagnosis for D-TGCT is broad due to the nonspecific finding of synovial hyperplasia and joint effusions, which can mimic common pathologies such as arthritis and other tumors (eg hemangioma, chondromatosis). Combined with the vague clinical presentation, this can often lead to significant delays in diagnosis (2–3 years on average) [12], which highlights the importance of appropriate imaging and biopsy for timely diagnosis and characterization of D-TGCT.…”

“…D-TGCT on MRI is characterized by low signal intensity areas of nodular masses with synovial thickening and cystic bone lesions sometimes intermixed with sparser foci of high signal intensity on both T1- and T2-weighted images representing lipid-laden macrophages or lower concentrations of hemosiderin [5], [12], [15]. These areas are surrounded by joint effusion, which appears as low signal on T1 and high signal on T2-weighted images [13].…”

“…In addition, gradient-echo images classically accentuate the susceptibility related to the underlying hemosiderin deposition known as “blooming” of the hemosiderin-laden nodular lesions [5], [13], [14]. MRI may provide a critical role in characterizing the lesion for surgical treatment [12].…”