Uterine Leiomyomas with Intravenous Leiomyomatosis: A Report of Two Cases.

PURPOSE: Intravenous leiomyomatosis (IVL) is a rare histological variant of uterine leiomyoma characterized by benign smooth muscle cells proliferating within the venous system. Despite its benign histology, IVL exhibits "quasi-malignant" behavior through intravascular extension, often leading to misdiagnosis as venous thrombosis or malignancy.

CASE PRESENTATION: We report two cases of uterine leiomyoma complicated by IVL. In Case 1, a 42-year-old woman with initially suspected iliac vein and inferior vena cava (IVC) thrombosis underwent contrast-enhanced computed tomography (CT), which demonstrated a continuous tumor extending from the uterus through the left ovarian vein and IVC into the right atrium. Based on the characteristic imaging findings and multidisciplinary evaluation, the preliminary clinical diagnosis of IVL was established and a one-stage combined surgery involving total hysterectomy, excision of the venous tumor, and cardiac resection under extracorporeal circulation was successfully performed. In Case 2, a 43-year-old woman with a history of myomectomy presented with broad ligament leiomyoma and intravascular extension into the iliac vein and IVC. The imaging appearance similarly raised strong suspicion for IVL rather than thromboembolic disease. The patient underwent total hysterectomy with bilateral adnexectomy and vascular reconstruction to remove the intraluminal tumor. Histopathology in both cases confirmed IVL. No recurrence was observed during the 22-month and 12-month follow-up periods, respectively.

CONCLUSION

These cases highlight the importance of considering IVL in women presenting with uterine masses and unexplained venous filling defects. Recognition of characteristic CT findings, particularly continuous intravascular extension along venous anatomy, is essential for differentiating IVL from deep vein thrombosis (DVT) and leiomyosarcoma. Early multidisciplinary assessment and complete surgical resection are critical for successful management and favorable long-term outcomes.