Pericardial Hemangioma: An 8-Year Diagnostic Odyssey of Recurrent Pleural Effusion.

BACKGROUND: Pericardial hemangioma is a rare benign tumor that can mimic chronic inflammatory disease. Distinguishing it from other pericardial masses is critical to avoiding a diagnostic delay. CASE SUMMARY: A 54-year-old woman presented with an 8-year history of recurrent effusions and was initially thought to have amyloidosis. Cardiac magnetic resonance (CMR) imaging identified a transverse pericardial sinus mass with characteristic T2 hyperintensity and centripetal enhancement, strongly suggesting hemangioma, which was confirmed histologically. Surgical excision was curative, with no recurrence at the 4-year follow-up. DISCUSSION: This case illustrates the "satisfaction of search" bias causing an 8-year diagnostic delay. It highlights the central role of comprehensive CMR tissue characterization in evaluating rare pericardial tumors, and the risk of anchoring on potentially misleading histopathological findings. TAKE-HOME MESSAGES: Pericardial hemangioma should be considered in unexplained recurrent effusions, particularly when corticosteroid therapy paradoxically reduces fluid volume and extensive autoimmune and oncologic work-up is unrevealing. Comprehensive CMR with tissue characterization is the key noninvasive modality, although histology remains confirmatory. A prior pericardial window may convert episodic pericardial effusion into chronic, treatment-refractory pleural disease by creating a preferential drainage pathway into the left pleural space.