A 52-year-old female with no significant past medical history presented to her primary care physician with bilateral lower extremity swelling and lower extremity venous varicosities, both of which had worsened during the previous 2 months.

She underwent a partial hysterectomy for uterine fibroids 8 years before the current presentation. Review of systems included worsening abdominal discomfort from enlarging uterine fibroids for 6 to 12 months before presentation. Physical exam revealed a lower abdominal mass originating from the pelvis and bilateral lower extremity edema along with dilated veins.

Preliminary laboratory tests with complete blood counts and comprehensive metabolic panel was unremarkable. An MRI of the abdomen and pelvis demonstrated a 24 cm × 11 cm × 21 cm heterogeneous mass arising from the uterine myometrium with areas of hemorrhage and necrosis (Figure 1). The mass extended into the extrauterine pelvic veins, inferior vena cava, and the right atrium and right ventricle.

Figure 1. Panel 1a shows a contrast-enhanced axial T1-weighted image of the abdomen with a filling defect in the inferior vena cava.

Images courtesy of M. Ghesani, MD

Panel 1b shows an axial T1W post-contrast image through the pelvis demonstrating a heterogeneous necrotic mass.

Panel 1c is a sagittal T1-weighted post-contrast image demonstrating the mass arising from the uterine myometrium.

Differential diagnosis at the time included both malignant and benign etiologies, such as leiomyosarcoma and IV leiomyomatosis. A PET/CT was done to assess malignant potential. It revealed a low-grade hypermetabolism of the uterine mass with a maximum standard uptake value of 2.7 and extensive tumor thrombus involving the extrauterine pelvic veins extending into the right ventricle with low-grade hypermetabolism (Figure 2).

Figure 2. PET/CT images of the pelvic mass show low-grade fluorodeoxyglucose uptake in the mass.

This could be suggestive of benign etiology such as IV leiomyomatosis (IVL), but a literature search did not reveal any reported cases of PET/CT findings in IVL for comparison. CT angiogram of the chest, abdomen and pelvis — performed for surgical planning — confirmed the above findings (Figure 3).

Figure 3. Coronal and sagittal images from CT angiogram demonstrate an extensive heterogeneously enhancing tumor originating in the uterus and extending into the inferior vena cava, right atrium and right ventricle.

The patient underwent a single-stage resection of the pelvic tumor, thrombectomy and thoracotomy for removal of the tumor in its entirety, including the right atrial and ventricular components. Her postoperative course was uneventful. Pathology of the resected tumor revealed benign proliferation of smooth muscle with intravascular extension consistent with IVL (Figure 4).

Figure 4. Gross specimen shows pink-tan benign smooth muscle neoplasm consistent with intravenous leiomyomatosis.

Discussion

IVL is a rare uterine smooth muscle tumor characterized by IV growth and extension of benign smooth muscle. The tumor originates in the pelvic veins and extends upward to varying distances, including the inferior vena cava, adrenal and renal veins, right heart (intracardiac leiomyomatosis) and pulmonary artery.

Pathogenesis is unclear, although it is postulated to be arising from uterine leiomyoma invading into the uterine vein and extending along the lumen of the major veins. The incidence of IVL is thought to be underestimated because, in the early stages, the tumor extension remains in the vessels of the myometrium and cannot be detected on imaging. The correct diagnosis relies on a high index of suspicion and should be suspected whenever an intravascular tumor is noted during surgery or microscopic analysis.

Lam and colleagues reported summary of 62 cases. In their series, the median age of presentation was 42 years. The most common presenting features included congestive heart failure, features of venous obstruction and abdominal distention. Other clinical features such as pelvic discomfort, low abdominal pain and irregular vaginal bleeding due to pelvic mass, uterine myoma, lower extremity edema due to inferior vena cava occlusion, dyspnea, chest pain and even sudden death due to mechanical obstruction of the heart have been reported by other authors.

More than 50% of the patients in the series had history of hysterectomy before the presentation as IVL. In these cases, there is a possibility that the IVL could have been missed at an earlier stage in the pelvic veins during the initial surgery.

Preoperative imaging is important to define the extent of tumor, as the presence of intrathoracic disease affects the surgical approach. CT angiogram with 3-D post-processing can show the path and extent of disease. Some of the features on the CT could be suggestive of IVL. These include pelvic masses that are continuous with the mass in the veins, inhomogeneous enhancement and extensive lesion.

Enhancement of the tumor thrombosis is similar to that of renal carcinoma, hepatocellular carcinoma and adrenal cortical carcinoma, but the lesion is more extensive in IVL. Differential diagnosis of IVL includes IV thrombus, leiomyosarcoma, right atrial myxoma and tumor thrombosis with malignant carcinoma. The history of past or present uterine myoma with the above-mentioned CT finding can help with the diagnosis.

Surgery remains the treatment of choice. Surgical management includes a total abdominal hysterectomy and bilateral salpingo-oophorectomy. The ovaries usually are removed, as these tumors are estrogen sensitive. Complete resection is mandatory. This may involve thoracotomy and cardiac surgery, including cardiopulmonary bypass depending on the extent of spread. Gross examination of the intravascular mass could show worm-like plugs of tumor, and histology usually demonstrates benign proliferation of smooth muscle with intravascular extension. Prognosis after surgery usually remains very good.

Munir Ghesani, MD, is an attending radiologist at St. Luke’s-Roosevelt Hospital Center and Beth Israel Medical Center, an associate clinical professor of radiology at Columbia University College of Physicians and Surgeons, and a HemOnc Today section editor. Nasima Jafferjee, MD, is a radiology resident at St. Luke’s-Roosevelt Hospital Center. Rangaswamy

Chintapatla, MD, is a fellow in hematology and oncology at St. Luke’s-Roosevelt Hospital Center. Peerapod Chiowanich, MD, is an assistant attending radiologist at St. Luke’s-Roosevelt Hospital Center. Darren Buonocore, MD, is a post-doctoral residency fellow in pathology at St. Luke’s-Roosevelt Hospital Center. Alan Benvenisty, MD, is chief of the division of transplant surgery at St. Luke’s-Roosevelt Hospital Center. Disclosure: Drs. Ghesani, Jafferjee, Chintapatla, Chiowanich, Buonocore and Benvenisty report no relevant financial disclosures.

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