Inflammatory pseudotumor (plasma cell granuloma) of the heart. Report of two cases and literature review.

We report pathologic findings in two patients with inflammatory pseudotumor of the heart. The first patient was a 15-year-old-boy who died suddenly and unexpectedly of myocardial ischemia caused by an angiocentric inflammatory pseudotumor affecting all of the major coronary arteries and some of their branches. Inflammatory pseudotumor was also centered around some intrasplenic arteries. The second patient was a 5-month-old girl who had subtotal resection of a mass in the right atrial free wall. Her inflammatory pseudotumor was confined to the myocardium and showed no angiocentricity. The patient is doing well 22 months after surgery. Inflammatory pseudotumor is a benign inflammatory response evoked by an unknown agent(s). In both patients, the inflammatory cells comprised a mixture of B and T lymphocytes. Among B cells, a mixture of kappa and lambda plasma cells was evident. A moderate number of tissue macrophages was also observed. The process is usually self-limited but may cause death if vital structures are involved.