A strange cause of portal hypertension: leiomyosarcoma of the portal vein.

Clinical History

A 44-year-old woman presented to our hospital with 1 month of abdominal discomfort. She had noticed an increase abdominal circumference, postprandial fullness and dark stools. Physical examination did not revealed masses or hepatomegaly. Laboratory data included anaemia (Hb 7.6 g/dl), amylase of 288 (25-125). Other biochemical parameters showed no alterations.

Imaging Findings

A triphasic contrast enhanced Multidetector Computed Tomography was performed. The CT demonstrated a big mass located on the portomesenteric axis, theoretical path of the portal vein, with a maximum diameter of 11.5 cm. This mass presented a soft tissue attenuation with a lot of vessels enhancing on the arterial phase; the vascularisation depending on the gastroduodenal artery, branches of the superior mesenteric and splenic arteries. Another finding was an early enhancement of the intrahepatic portal branches suggesting arteriovenous fistulas, sign of malignancy.

The main portal vein was unidentifiable at the hepatic hilum and a cavernomatous transformation was present. There was also a tumour thrombus within the superior mesenteric vein. Multiplanar reconstructions showed that the pancreas was undamaged. The patient presented a lot of collateral veins, ascites and an enlarged spleen of 15 cm, secondary to portal hypertension. Two metastatic lesions were present in the left liver lobe, and pathological nodes.

Discussion

Leiomyosarcomas are a rare entity but the most common type of soft tissue sarcoma. Leiomyosarcomas with origin in vessels are less frequent than those that arise from visceral smooth muscle like intestine or uterus [1]. Two hundred vessels sarcomas have been reported arising from various venous structures: cava (the most common site of leiomyosarcoma) [2], iliac, renal and pulmonary veins. Predominantly, they arise from large and medium sized blood vessels; three cases of mesenteric vein, three of portal and one of splenic vein have been reported.

In general, the symptoms are abdominal discomfort with epigastric and hypocondrial pain, normally with postprandial fullness and abdominal bloating. All the patients in the literature with leiomyosarcomas on the splanchnic territory (superior mesenteric, splenic or portal vein) are females except one [3, 4].

Because of the relative rarity of soft tissue sarcomas, and not much frequency of vessel sarcomas, it is important for the radiologists to know the main findings and characterisation of this disease. About a 50 % of leiomyosarcomas are located in intra or retroperotineal sites, but it may be found in any anatomic location. The most common location of vascular tumours is the inferior vena cava [2].
A MD-CT can suggest with high accuracy a vascular origin of a mass: a soft tissue and hypervascular lesion that causes an occlusion of a vessel, because of the tumoral entity of the thrombus. An extensive collateral circulation, splenomegaly, ascites and probably, liver metastasis are frequently present [5].

The treatment for these tumours is a radical excision followed by venous reconstruction. Because of the high risk for recurrence, adjuvant chemotherapy is needed. There is no evidence about the benefit of the radiotherapy, but it is often used [6]. The poor prognosis of venous leiomyosarcoma is due to its high local recurrence and the tendency to metastatic spread [4]. The knowledge of the radiologist may suggest the diagnosis preoperatively.

Differential Diagnosis List

Final Diagnosis

Leiomyosarcoma of the portal vein with liver metastasis.

URL:	https://www.eurorad.org/case/9921
DOI:	10.1594/EURORAD/CASE.9921
ISSN:	1563-4086