Fluorodeoxyglucose (FDG)-Avid Pericardial Effusion With Reactive Mesothelial Proliferation Mimicking Malignancy

Figures

• 

  Figure 1. Cardiac MRI Demonstrating Pericardial Effusion and Inflammation Cardiac magnetic resonance imaging (MRI) revealed mild pericardial thickening (up to 5 mm) with late gadolinium enhancement (red arrows), indicating active pericardial inflammation. No myocardial edema or delayed myocardial enhancement was observed, and left ventricular systolic function was preserved (left ventricular ejection fraction (LVEF) 78%). A small left-sided pleural effusion was also noted. These findings supported inflammatory pericarditis without myocardial involvement and helped exclude constrictive physiology.

• 

  Figure 2. PET-CT Showing FDG-Avid Pericardium and Lymphadenopathy Whole-body F18-fluorodeoxyglucose (FDG) PET-CT demonstrated moderate FDG uptake along the left pleura and pericardium (SUVmax 3.1) (A), with prominent hypermetabolic lymph nodes in cervical, mediastinal, and abdominal stations (SUVmax up to 13.7) (B). No discrete mass lesion or primary malignancy was identified. These findings raised concern for malignancy but were later confirmed to represent a chronic inflammatory response with reactive mesothelial proliferation. SUVmax = maximum standardized uptake value

• 

  Figure 3. Circular Timeline of Clinical Course and Diagnostic Workup This figure summarizes the chronological sequence of symptom onset, prior outside-hospital drainage procedures, worsening edema before admission, confirmation of large pericardial effusion at the current institution, in-hospital multimodality diagnostic evaluation, and initiation of corticosteroid therapy before discharge with clinical improvement. Image made using Canva (Canva Inc., San Francisco, CA).