Para-atrial non-acute mediastinal hematoma after left atrial maze procedure mimicking tumor in a patient with treated melanoma

The cox maze iii procedure is considered the gold standard open surgical procedure for management of atrial fibrillation. this article outlines a unique case of a para-atrial mediastinal hematoma following a bilateral thoracoscopic left atrial maze procedure mimicking malignancy. a 60-year-old male, with past history of melanoma, underwent bilateral thoracoscopic left atrial mini maze procedure with radiofrequency energy and exclusion of the left atrial appendage. seven months later, a chest computed tomography (ct) scan was performed to evaluate for pulmonary embolism. the ct scan unexpectedly showed an ill-defined, heterogeneous para-atrial mass immediately superior to the left atrium concerning for tumor and mediastinal adenopathy. the mass was moderately hypermetabolic on subsequent 2-[fluorine-18]fluoro-2-deoxy-d-glucose (fdg) positron emission tomography (pet) scan. a follow-up pet/ct three months later demonstrated near-complete resolution of the para-atrial mass with minimal residual hematoma. non-acute mediastinal hematoma following a maze procedure can potentially be confused with a tumor mass and/or lymphadenopathy on ct and fdg pet/ct. with knowledge of the potential for false-positive fdg uptake in a hematoma, the lesion was monitored, and unnecessary biopsy was avoided.