Retroperitoneal liposarcoma with pancreatic metastasis and gastric cancer: a case report.

On computed tomography scanning, a 63-year-old man with vomiting and anorexia was discovered to have a mass in the pancreatic body and a retroperitoneal mass extending to the right lobe of the liver. An esophagogastroduodenoscopy revealed an advanced gastric carcinoma in the middle gastric body, and a biopsy specimen revealed a poorly differentiated adenocarcinoma. The pancreatic and retroperitoneal masses were considered metastatic lesions of gastric cancer, and a biopsy was taken from the pancreatic lesion using endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA). The histology of the EUS-FNA pancreatic specimen revealed atypical spindle-shaped cells and increased stromal collagen fibrosis, and liposarcoma was considered. Conversely, a percutaneous ultrasound-guided biopsy was taken for the retroperitoneal lesion, and the histology revealed that it was a dedifferentiated liposarcoma. On the basis of histopathological and imaging findings, the retroperitoneal liposarcoma was identified as the primary lesion, the pancreatic lesion as a metastasis of the primary liposarcoma, and the gastric carcinoma as an independent tumor. As far as we know, there have only been three reports of metastatic pancreatic liposarcoma diagnosed via EUS-FNA. In this case, the patient also had gastric cancer, and EUS-FNA was helpful in differentiating metastatic pancreatic tumors from gastric cancer.