Clinicopathologic features and clinical outcomes of intravenous leiomyomatosis of the uterus: A case series.

Rationale: Intravenous leiomyomatosis (IVL) is a rare and special type of smooth muscle tumor originating in the uterus. It is classified as a benign disease according to its histological features but shows the behavioral characteristics of a malignant tumor. It is easily misdiagnosed and recurrent. The purpose of this study was to retrospectively analyze clinicopathological data of 25 cases of IVL in order to enhance clinicians' understanding of this rare disease.

Patient Concerns: We screened and identified 25 cases of IVL at our hospital from October 2013 to January 2020. Five patients had tumors.

Diagnoses: The diagnosis in each case was pathologically confirmed after surgical treatment.

Interventions: All patients were managed surgically. Although the surgical procedures were different, the surgical approach was geared towards achieving complete excision. Three patients received hormonal therapy with gonadotropinreleasing hormone agonists after surgery.

Outcomes: We retrospectively reviewed all medical records and analyzed the clinicopathologic features and clinical outcomes of this disease as well as the correlations between the clinical features and risk of recurrence. Neither the symptoms nor the preoperative imaging results were suggestive of IVL in any of the cases. Except for two patients who were lost to follow-up, twenty-three patients who were followed up are still alive. Three patients experienced a recurrence.

Lessons: The clinical manifestations and ultrasound images of IVL in the early stages are not typical; thus, IVL is easily misdiagnosed as uterine leiomyoma. Radiologists, pathologists, and surgeons should have a thorough understanding of IVL and a high index of vigilance for IVL in clinical practice. Surgery should always be aimed at achieving complete tumor excision. Patients with large lesions (≥7 cm) and lesions extending to the broad ligament may have an increased risk of recurrence. Early detection, diagnosis, and treatment are very important; once the diagnosis is confirmed, regular follow-ups are crucial.