The largest single-center report on intravenous leiomyomatosis and development of a classification to guide surgical management.

Background: Intravenous leiomyomatosis (IVL) is a rare neoplasm; the accumulated knowledge about the characteristics and prognosis of this tumor has been derived mainly from isolated case reports with no comprehensive research. In this study, we reviewed our institution's experience with IVL over a 20-year period and developed a classification system that can be used to guide surgical management.

Methods: The study had a retrospective cohort design and included patients who underwent resection of IVL at our institution between January 2002 and December 2022. Perioperative parameters were then collected among four stages of our proposed classification. The long-term outcomes, oncologic prognosis, and factors associated with recurrence were analyzed.

Results: A total of 216 patients were included (stage 1, n = 92; stage 2, n = 39; stage 3, n = 76; stage 4, n = 9). The mean follow-up duration was 26.34 months, during which 18 patients (9.7%) in the complete resection group had recurrence, and 12 (39.0%) in the incomplete resection group showed disease progression. Recurrence or progression of residual disease was associated with adjuvant aromatase inhibitor therapy and maximum tumor thrombus diameter but not with total hysterectomy and bilateral salpingo-oophorectomy, age, or postoperative treatment with a gonadotropin-releasing hormone agonist therapy.

Conclusions: This is the largest single-center report on IVL published to date and provides valuable information on its clinical features and long-term outcomes, as well as surgical technique. Our classification system can be used to evaluate the extent of lesion involvement and guide surgical management.