Intracardiac leiomyomatosis: Report of two cases.

Intravenous leiomyomatosis is an example of unusual growth patterns that is sometimes exhibited by uterine leiomyomas, characterized by smooth muscle proliferations within the uterine or pelvic veins. Extension into the heart via the inferior vena cava is even rarer and is designated as intracardiac leiomyomatosis. This is a report of two such cases that had preoperative diagnoses of a thrombus and right atrial myxoma, respectively.