Malignant soft tissue tumors (STT) account for <1% of malignant tumors in adults. LMS make up less than 5% of these STT, and specifically vascular LMS accounts 0.7% of all STT . Two percent of LMS originates from the vascular system being IVC, the most commonly involved . Retroperitoneal sarcomas are uncommon, constituting 10% to 15% of all soft tissue sarcomas (STS) with an average annual incidence of approximately 2.7 cases per million population . The mean age of presentation is 53 years with a female:male ratio of 3:1 .
IVC LMS usually has a delayed clinical presentation due to slow growth and retroperitoneal location with intraluminal and/or extraluminal extension and spreading by local expansion along adjacent low-resistance structures [1,6]. Metastases are initially spread hematogenously and subsequently through lymph nodes and can involve the liver, lung, and/or bones . Anatomically, IVC is divided in three segments, and according to the level affected by the tumor, the symptoms may vary. Segment I involvement (infrarenal IVC) usually presents with pedal edema and abdominal distention. Segment II (middle segment of IVC, from renal to hepatic veins) with nephrotic and/or Budd-Chiari syndrome. Segment III (above hepatic veins) with pulmonary embolism [1,6,9].
Retroperitoneal LMS is more often diagnosed on CT or MRI. CT scan is the imaging modality of choice for evaluation of the tumor . Coronal and sagittal slices of contrast-enhanced CT can reliably detect the origin and extension of it or if metastases are present, helping the preoperative surgical planning and determining the prognosis. Hypodense retroperitoneal mass involving the IVC with heterogeneous post contrast enhancement is the most common imaging presentation. Hence, an IVC LMS should be suspected whenever it is seen as heterogeneously enhancing as a retroperitoneal mass along the IVC [6,14]. Radiographic findings that indicate unresectability are peritoneal implants, distant metastases, involvement of the root of the mesentery, and spinal cord involvement . In our case, we decided to confirm the diagnosis with biopsy of the tumor in order to be sure that it was not a recurrence of her previous colon cancer.
The only curative treatment that has been proved for IVC LMS is complete resection of the tumor with free margins. Adjuvant radiation and chemotherapy remains controversial and unclear [2,4,7,12,16,17]. Surgical options include partial resection and primary cavoplasty, complete resection and graft placement, and ligation of IVC. The latter can be performed uneventfully if a good collateral network has been developed before IVC occlusion or if it has not affected segment III IVC as it happened in our patient [3,7-9].
It has been described by Ferrario et al. on a study of 130 patients with retroperitoneal STS that local recurrence rate after local excision is 63% and after wide excision 39% (P < .02). The estimated 5- to 10-year survival with local recurrence was 54% and 39%, respectively, and without local recurrence 66% and 58%, respectively (P < .05). The overall estimated 5-year survival from the first surgery was 60% and 10-year survival 48%. Prognostic factors for survival were the grade (P < .001) followed by the procedure, wide versus local excision (P < .01), whereas tumor size was not significant . According to Italiano et al. on a study of 1,472 patients with sarcoma, vascular origin is an independent adverse prognostic factor for metastasis-free survival and overall survival . Meanwhile, Laskin et al. on a study of 40 patients with IVC LMS demonstrated that level III IVC and right atrial involvement by sarcoma, intraluminal growth, compromised liver, and residual postsurgical macroscopic disease negatively impact on clinical course of the disease .