Intravenous leiomyomatosis

Intravenous leiomyomatosis (IVLM) is characterized by the extension into venous channels of histologically benign smooth muscle tumour arising from either the wall of a vessel or from a uterine leiomyoma. 

Intravenous leiomyomatosis should not be confused with benign metastasizing leiomyoma, in which a benign uterine leiomyoma is associated with a benign smooth muscle tumor located in the parenchyma of a distant organ, such as lung. Intravenous leiomyomatosis is confined to vessels, whereas benign metastasizing leiomyoma shows no relation to vascular channels.

Epidemiology

Fewer than 100 cases have been reported in all, and only 14 cases involved intracardiac extension from the IVC. In one reported case, this slowly growing invasive neoplasm extended not only into the heart but into both pulmonary arteries as well. The etiology of IVLM is unclear. All described patients are female, and most are white, premenopausal, and parous. The median age is 45 years, with patients ranging from 26 to 70 years old.

Clinical presentation 

Patients may be asymptomatic or have symptoms of uterine leiomyomas. Patients with obstruction of the right atrium may present with syncopal episodes, dyspnea on exertion, shortness of breath, etc. 

Treatment and prognosis

The tumour is typically slow growing, and the prognosis is favorable. Although embolization of the tumor represents a theoretical risk, this has not been reported. Recurrence can occur and a repeat surgery may be necessary. Most reported deaths involved extension of the tumor into the heart, with death due to mechanical obstruction rather than the neoplastic process per se

Differential diagnosis

When the IVC is involved the differential diagnosis should include 

• renal malignancies 
  • renal cell cancer
• primary leiomyoma or 
• sarcoma
• thrombosis of the IVC. 

IVLM should be considered in young women with cardiac symptoms who have a right atrial mass as well as a pelvic mass or who have previously undergone hysterectomy for leiomyoma uterus with intravenous involvement.