Intravenous leiomyomatosis disguised as a large deep vein thrombosis

Intravenous leiomyomatosis is a benign smooth muscle tumor which despite its histology can have devastating consequences. Furthermore, the clinical manifestations are variable and nonspecific, typically leading to delayed or missed diagnosis. Thus, it is critical for clinicians to be aware of this condition and have a high index of suspicion in a middle-aged woman with a history of uterine leiomyoma presenting with an inferior vena cava mass to enable early diagnosis and treatment. We report a case of a large intravenous leiomyoma which was initially considered to be a very large deep venous thrombosis; with thorough preoperative planning, it was successfully removed intact and in entirety with a single-stage operation.