Léiomyosarcome portal : une localisation extrêmement rare !

Leiomyosarcomas of large vessels are rare. It is a malignant tumour and the vast majority of these tumours arose from the inferior vena cava. We report a rare case of portal vein leiomyosarcoma, in a 56-years-old female patient admitted for chronic abdominal pain with abdominal mass in the right hypochondrium all evolving in a context of deterioration in general condition. We performed an abdominopelvic CT scan and then a MRI with contrast agent which objectified a large tissue mass containing areas of necrosis at the level of the duodeno-pancreatic compartment communicating at a large angle with the portal trunk over its entire length from the hepatic hilum to the spleno-mesenteric confluence responsible for a portal cavernoma downstream. This is associated with multiple secondary nodular tissue hepatic lesions. We also noted a respect for the fatty border separating the mass of the duodenal tract and the head of the pancreas, and also the absence of dilation of the pancreatic ducts making a pancreatic origin unlikely. To eliminate a duodenal origin of the mass we performed an upper digestive endoscopy which came back without any abnormality. An ultrasound-guided trans parietal biopsy of a secondary hepatic lesion was done and the pathological result of which speaks of a secondary hepatic lesion of a leiomyosarcoma.