Abstract： Objective:To investigate the clinical features, treatment and recurrence factors of intravenous leiomyomatosis (IVL) confined to the pelvic cavity after the operation.Methods:The clinical data of 81 patients who underwent surgery and were pathologically diagnosed with IVL at Women′s Hospital, School of Medicine, Zhejiang University from January 2014 to March 2021, were analyzed retrospectively to explore the influencing factors of postoperative recurrence of IVL, including age, gravidity and parity, surgical methods, intraoperative conditions and so on.Results:(1) Clinical features: the age of 81 IVL patients was (43.9±8.1) years old; increased menstrual volume in 26 cases (32%, 26/81), prolonged menstrual period in 31 cases (38%, 31/81), frequency and urgency to urinate in 4 cases (5%, 4/81), abdominal pain and abdominal distension in 8 cases (10%, 8/81), and pelvic masses in 34 cases (42%, 34/81). IVL was diagnosed right in 4 of 72 patients (6%, 4/72) underwent preoperative ultrasound, right in 11 of 51 patients (22%, 11/51) underwent magnetic resonance imaging (MRI), and right in 4 of 19 patients (4/19) underwent CT. (2) Treatment: all patients with IVL underwent surgical treatment. Surgical procedure: myomectomy in 37 cases, total hysterectomy and bilateral salpingectomy in 19 cases, total hysterectomy and bilateral salpingo-ophorectomy in 25 cases. Surgical approach: hysteroscopic operation in 6 cases, transabdominal operation in 52 cases, laparoscopic operation in 23 cases. Fifty-three cases underwent rapid intraoperative pathological examination, 17 cases (32%, 17/53) of them were diagnosed right as IVL. (3) Influencing factors of IVL postoperative recurrence: among 81 patients with IVL, 3 cases were lost to follow-up, and 8 cases (10%, 8/78) had recurrence during follow-up. Age<35 years, number of pregnancies<2, number of births<2, number of fibroids ≥10, abnormal appearance of fibroids (long, vermicular, beadlike, cystic, etc.) and IVL invasion into adjacent vessels were all the risk factors influencing postoperative recurrence of IVL (all P<0.05). Methods of operation, ovariectomy or not, IVL invasion or not, maximum diameter of IVL, abundant blood vessels near uterine fibroids were not associated with postoperative recurrence of IVL (all P>0.05). Conclusions:The clinical manifestations and preoperative auxiliary examination of IVL are lack of specificity. Doctors need to pay attention to young patients with uterine fibroids, and choose the appropriate surgical scope when the characteristic manifestations of IVL be found during the operation, or the right diagnoses of IVL in the surgery′s rapid intraoperative pathology be examined, and should remove the IVL lesions to reduce the recurrence as far as possible.