Right atrial extension of a giant retroperitoneal leiomyosarcoma.

Leiyomyosarcoma of vascular origin is uncommonly seen but mostly occurring in the inferior vena cava. We report a case of young male who presented with giant retroperitoneal leiyomyosarcoma which extended into the right atrium along Inferior vena cava.

Introduction

Out of many abdominal tumors which invade inferior vena cava and extend into the right atrium, renal cell carcinoma is the most frequent one.[1] Leiomyosarcoma of the inferior vena cava and adrenal gland are among the subtypes of retroperitoneal sarcomas which have tendency to invade inferior vena cava and extend into the right atrium.[23]

We hereby present a case of giant retroperitoneal leiomyosarcoma which extended into the right atrium along inferior vena cava. Our case highlights very uncommon type of retroperitoneal tumor with giant size and right atrial extension.

Case Report

A 32-year-old male was admitted with history of upper abdominal discomfort and pain which had progressed over 2 months. A large firm mass was palpated in the right hypochondrium and lumbar region. Triple phase computed tomography (CT) of the abdomen was performed, showed a large heterogeneous infiltrating mass in the right upper retroperitoneum. The mass measured 23 cm × 17 cm × 17.5 cm in dimensions. The lesion extended from the undersurface of right lobe of liver (which is infiltrated by the mass) to the level of the right renal hilum. Antero-posteriorly the mass extended from the right paravertebral region to the anterior abdominal wall. The hepatic flexure and ascending colon were displaced anteriorly by the mass. The anteromedial relations of the mass were antropylorus, splenoportal axis, the displaced and invaded inferior vena cava and the pancreatic head. The abdominal aorta was medial to the lesion. The right adrenal gland was not visualized separately. The upper pole of right kidney was infiltrated by the mass with posterior displacement of hilar vessels. The mass showed areas of hemorrhage, necrosis and solid enhancing nodular tissue within it.

The tumor thrombus in inferior vena cava extended into the hepatic part of inferior vena cava and right atrium. The azygous system was dilated as a result of the inferior vena cava obstruction. Moderate ascites was also seen [Figure 1].

Figure 1

Computed tomographic images of the patient. (a) Coronal section shows a large heterogeneous mass in the right hypochondrium and lumbar region extending into right atrium. (b) The mass is invading the right renal cortex. Necrotic areas are represented by the internal non enhancing areas. (c) Renal hilar vessels are displaced posteriorly by the mass lesion. (d) Right atrial extension of the mass is seen as filling defect in the contrast filled cardiac chamber. (e) Hepatic parenchyma is infiltrated by the mass with prominent azygous-hemiazygous system. (f) Prominent azygous vein is seen joining superior vena cava representing collateral channels becoming prominent due to inferior vena cava obstruction

The possibility of renal tumor was excluded by the fact that the epicenter of the mass was outside the kidney with secondary involvement of the renal parenchyma. The imaging differentials were primary retroperitoneal tumor, adrenal tumor, and tumor arising from the inferior vena cava.

An ultrasound guided biopsy was performed and samples were sent for histopathological evaluation. Histopathological sections showed a tumor composed of spindle to oval pleomorphic cells with eosinophilic cytoplasm, indistinct cell borders, and oval to elongated moderately pleomorphic nuclei. Few bizarre cells and an occasional mitosis were also noted. On immunohistochemistry, the tumor cells were positive for smooth muscle actin, epithelial membrane antigen, focally positive for desmin and negative for cytokeratin, S-100 protein, CD117, and CD10 [Figure 2].

Figure 2

(a) H and E sections with × 40 magnification shows (a) spindle cell tumor with moderately pleomorphic cells and an occasional bizarre cell, (b) intersecting fascicles of spindle cells with mitotic figures. Immunohistochemistry study of the tissue specimen showed positive staining for (c) smooth muscle actin, (d) epithelial membrane antigen. Immunohistochemistry study of the tissue specimen showed negative staining for (e) cytokeratin. (f) S-100

The histopathological impression was high grade leiyomyosarcoma. Clinico-radiological correlation led to the diagnosis of leiomyosarcoma arising from inferior vena cava, adrenal, or primary retroperitoneum.

Only treatment for retroperitoneal leiomyosarcoma is surgical resection with clear margins followed by radiotherapy and/chemotherapy. Before histopathological diagnosis was made, patient received supportive management including analgesics. Due to the poor general health status, the patient expired without any further intervention.

Discussion

Leiomyosarcoma is a malignant tumor of smooth muscle cells which originate most commonly in the uterus and retroperitoneum.[4] In the retroperitoneum, the most common site of origin is inferior vena cava.[5] Leiomyosarcoma of vascular origin is an uncommon tumor with predilection for the inferior vena cava. Conversely, primary malignancies of the inferior vena cava are uncommon, with leiomyosarcoma representing the vast majority.[6] leiomyosarcoma of inferior vena cava was first described by Dzsinich et al.[7] in 1992. Contrary to our case, leiomyosarcoma of inferior vena cava is four times more common in women and is mostly diagnosed in the sixth decade of life.

Leiomyosarcomas of the inferior vena cava are categorized by the part of inferior vena cava which is involved by the tumor [Figure 3].

Figure 3

Segments of inferior vena cava for the categorization of leiomyosarcoma

Level I (lower segment): Represents the portion of inferior vena cava below the renal veins.

Level II (middle segment): Represents the portion of inferior vena cava between renal veins and hepatic veins.

Level III (upper segment): Represents the portion of inferior vena cava between hepatic veins and right atrium.

According to the international registry of inferior vena cava leiomyosarcomas, lower (44.2%) and middle (50.8%) portions of inferior vena cava are most commonly affected by leiomyosarcomas, whereas the upper third region is least commonly involved (4.2%).[5]

Due to its slow rate of growth, inferior vena cava leiomyosarcomas remain asymptomatic for long time. This leads to the delayed diagnosis with dismal prognosis. Leiomyosarcomas involving inferior vena cava is intra-luminal in only 5% cases. In rest 95%, extraluminal growth is seen which can be mistaken for masses of adjacent organs and so the differential diagnoses should include primary tumors of these organs.[8] Preoperative assessment for resectability requires modern imaging techniques such as ultrasonography, echocardiography, CT, and magnetic resonance imaging (MRI).[9]

Combination of modern vascular surgery with chemotherapy and/or radiotherapy is required for proper management.[10] Aggressive surgical removal with negative margins is essential followed by venous reconstruction by prosthetic replacement of the inferior vena cava whenever considered necessary. The material of choice for prosthetic replacement is reinforced polytetrafluoroethylene.[11]

Kieffer et al.[9] evaluated 22 cases of leiomyosarcomas of inferior vena cava and concluded that creation of an arterio-venous fistula eliminates the need for long-term anticoagulation therapy and ensures patency.

Conclusion

This case report shows that retroperitoneal leiomyosarcomas can invade inferior vena cava and right atrium as can other renal and hepatic malignancies and require CT or MRI and image-guided biopsy for definitive preoperative diagnosis.

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Conflicts of interest

There are no conflicts of interest.