Detection of Pericardial Thymoma by Cardiac Magnetic Resonance Imaging

BACKGROUND: Cardiac magnetic resonance imaging (cMRI) tissue characterization is important for classifying cardiac masses into benign and malignant. Primary cardiac tumors are rare. Occasionally, thymomas can present as ectopic masses in the pericardium. CASE SUMMARY: A 25-year-old woman presented with chest pain. cMRI revealed a heterogeneous mass which was isointense to the myocardium in T1, hyperintense in T2 images, demonstrated contrast enhancement on perfusion imaging suggestive of vascularity and a constellation of features on parametric mapping and phase-sensitive inversion recovery sequences, which raised suspicion for a malignant tumor. Histology revealed a type B1 thymoma. DISCUSSION: cMRI techniques, including parametric mapping, play a crucial role in the anatomic and tissue characterization of masses, which guides staging and surgical planning if indicated. To our knowledge, this is the first reported case of a cardiac thymoma evaluated with modern cMRI techniques. TAKE-HOME MESSAGE: Atypical cMRI appearance of pericardial masses should prompt consideration of rare tumors such as thymomas.