Thymic cancer: A not-so-indolent cause of pericardial effusion.

The incidence of pericardial effusion in the U.S. is roughly 3.4% [1]. While most causes of pericardial effusions are indolent and transient, malignancy is a much more insidious cause that cannot be overlooked. Most cases of documented pericardial effusion secondary to malignancy have been due to mass effect from benign thymic tumors, such as thymomas. Our case highlights a 41-year-old male who presented with a dry cough and epigastric pain, found to have a large pericardial effusion and incidental thymic mass. The mass was biopsied and found to be keratinizing squamous cell carcinoma. This case expands our knowledge base as clinicians that pericardial effusions can be caused by malignant extension of tumors, rather than simply by mass effect of benign tumors.