Huge retroperitoneal dedifferentiated liposarcoma presented as acute pancreatitis: report of a case.

A 74-year-old male with abdominal pain was admitted to the emergency room in our hospital. The high value of serum amylase was shown in his blood test. The postcontrast computed tomography (CT) showed the huge retroperitoneal tumor with a thin-walled mass occupying most of the part of the right retroperitoneal space. The tumor spread into the soft tissues around the pancreas; as a result, the duodenum was compressed and the pancreas was displaced to the right side. The irregular pancreatic outline, obliterated peripancreatic fatty tissue and fluid in the left anterior pararenal space were revealed, so acute pancreatitis was diagnosed. The diagnostic biopsy of retroperitoneal tumor was done, and the pathological findings of retroperitoneal mass revealed dedifferentiated liposarcoma. The medical treatment against acute pancreatitis was performed firstly. After the patient recovered from that, the surgical resection of the tumor with the right kidney and right adrenal gland was completed successfully. The patient remained well, without any evidence of recurrence three months after surgery. However, the histology showed dedifferentiated liposarcoma; therefore, postoperative regular examination is necessary.