Puzzling obstructive tumor in the right heart: A large intravascular leiomyomatosis with intracardiac extension.

Objective: Intravascular leiomyomatosis (IVL) is a rare benign tumor capable of hematogenous spread. Clinical presentation is heterogeneous depending on the destination organ, which often delays identification. Key steps: A 38-year-old female with a recent history of hysterectomy presented with dyspnea and dizziness. Initial workup revealed a huge obstructive growth in the right heart chambers. A thrombus-in-transit was the most likely preliminary diagnosis. Further thorough assessment reduced the likelihood of a thrombus and increased suspicion of a benign tumor. A large IVL with intracardiac extension was then considered. The mass was completely resected through a combined one-stage approach, and IVL was confirmed pathologically. The patient was well-educated about the importance of periodic surveillance for the reported high recurrence rates. What we have learned? IVL is a rare benign tumor that behaves like malignancy and, hence may have nonspecific presentations. Thorough clinical evaluation and collaborated multi-modality imaging are critical keys to the appropriate diagnosis.