A 45-year-old woman with pulmonary venous metastasis from uterine leiomyosarcoma
A 45-year-old woman reported she had experienced bloating and felt lower abdominal pressure for the past 3 months.
Ultrasound showed a large uterine fibroid. Further evaluation with MRI of the abdomen and pelvis raised the possibility of uterine malignancy, prompting hysterectomy and bilateral salpingo-oophorectomy.
MRI also showed nodules in the right lung base. On surgical pathology, the findings were consistent with a leiomyosarcoma 11.5 cm in size.
A diagnostic chest CT with contrast confirmed lung nodules that were suspicious for metastases. Further evaluation with PET/CT revealed intense 18F-fluorodeoxyglucose (FDG) uptake within these nodules in the right perihilar region and in the right lower lobe.
MRI of the pelvis revealed an enlarged uterus containing an 11.4-cm-by-8.2-cm lesion within the endometrial cavity with marked restricted diffusion and heterogeneous enhancement, representing a densely cellular lesion (Figures 1-4).
Chest MRI demonstrated a 1-cm enhancing right lower lobe lung nodule. Chest CT confirmed this nodule and revealed an additional 2.5-cm lobulated perihilar nodule in the right upper lobe overlying the fissure with an oblong tubular component extending into the right superior pulmonary vein (Figures 5 and 6). There was no mediastinal lymphadenopathy.
PET/CT showed intense FDG uptake, with standard uptake value reaching up to 27 within the right perihilar lung nodule and 18.2 in the right lower lobe nodule, consistent with lung metastasis. (Figures 7-9).
Uterine leiomyosarcoma are the most common malignant gynecologic mesenchymal tumor, and they frequently are accompanied by metastases.
The malignancy most commonly arises de novo, though rarely it results from sarcomatous transformation of benign preexisting leiomyoma. It is an aggressive malignancy, with reported 5-year survival ranging from 20% to 70%. The risk for recurrence varies from 45% to 73%.
It generally occurs in women aged older than 40 years, with a median age at diagnosis of 60 years.
Long-term tamoxifen use, black race and prior pelvic radiation are known risk factors. Symptoms are nonspecific, such as abnormal vaginal bleeding, a palpable pelvic mass and pelvic pain.
The most common metastatic sites are the lung (67.7%), cranial/intracranial (16.2%), skin/soft tissues (15.3%) and bone (13.8%). Other sites include the thyroid, salivary gland, heart, liver, pancreas, adrenal gland, bowel and breast.
MRI plays a major role in the assessment of gynecologic neoplasms, especially in differentiating between the benign leiomyoma and leiomyosarcoma. It also assists in the assessment of invasion depth, spread to adjacent organs, lymph node involvement, and distant soft tissue and bone marrow metastases.
On MRI, leiomyosarcomas present as a large heterogeneous mass of low intensity on T1, or intermediate to high intensity on T2 with lobulated and irregular margins. Hemorrhage and foci of calcification are commonly seen.
The presence of irregular lobulated margins, necrosis and rapid growth are the most suggestive features. Using the analysis of T2 signal intensity, b1000 images and apparent diffusion coefficient map, MRI can differentiate leiomyoma from leiomyosarcoma with more than 90% accuracy. However, contrast-enhanced MRI is preferable to the diffusion-weighted MRI alone.
Vascular invasion of the pulmonary vein is frequently seen with primary intrathoracic malignancies, such as primary lung carcinoma, thymic tumors and extrathoracic malignancies, such as renal cell carcinoma, hepatocellular carcinoma, neuroblastoma and Wilms’ tumor.
Sarcoma, particularly uterine leiomyosarcoma, also are noted to have vascular emboli from invasion of pelvic veins or inferior vena cava.
In this case there was invasion of the pulmonary vein from the lung metastasis from primary leiomyosarcoma.
Intravascular leiomyosarcoma is a distinct entity in which uterine leiomyosarcoma spreads through venous tumor emboli into the inferior vena cava, heart and lung vessels. In our case, the parenchymal metastatic nodule was contiguous with the pulmonary vein filling defect. The recommended treatment for an oligo metastatic lung lesion from leiomyosarcoma is surgery.
Leiomyosarcomas are difficult to diagnose on clinical evaluation alone. Imaging, particularly MRI, plays a major role in detecting features suspicious for malignancy.
Leiomyosarcoma are known to result in distant metastases, which can be detected with imaging studies such as CT or PET/CT.
McDonald DK, et al. Cardiovasc Intervent Radiol. 2007;30:140-142.
Sato K, et al. Am J Obstet Gynecol. 2014;doi:10.1016/j.ajog.2013.12.028.
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Munir Ghesani, MD, FACNM, is assistant professor of radiology and director of PET/CT fellowship at NYU Langone Medical Center in New York. He also serves as a HemOnc Today Editorial Board member. He can be reached at firstname.lastname@example.org.
Ajit Karambelkar, MD, is a PET/CT fellow at NYU Langone Medical Center.
Disclosure: Ghesani and Karambelkar report no relevant financial disclosures.