Introduction: Dedifferentiated retroperitoneal liposarcoma (RPLS) is a rare, biologically heterogeneous tumor that presents with a morphological spectrum and is histologically challenging to diagnose. The tumors typically consist of a single tumor characterized as both poor and well dedifferentiated liposarcoma and non-lipomatous sarcoma. Presentation is typically symptomatic with abdominal pain, ascites, palpable mass, or the rare lower gastrointestinal bleed. Treatment consists of neoadjuvant radiation, surgery, and chemotherapy based on different staging systems used to identify the subtype and histology grade. The success of therapy depends on staging and grading of the tumor. We report a case of dedifferentiated RPLS presenting as upper gastrointestinal bleeding. [1]
Case Description/Methods: A 68-year-old male presented to the emergency department with three days of melena and shortness of breath. On exam, the patient was alert and oriented x 3. Afebrile. Blood pressure was 109/67 and heart rate 95 BPM. Oxygenation saturation of 93% on 3 L of oxygen by nasal cannula. The abdomen was soft, nontender, with a firm mass-like structure palpated in the right upper quadrant. Labs revealed hemoglobin of 7.9. CT imaging showed a large mass abutting the duodenum, right kidney, measuring 18 x 13 x 15 cm. Margin with duodenum very difficult to discern suggesting may be invading or rising from duodenum. Due to anemia with melena and CT findings, an EGD and upper EUS with FNA were completed. EGD revealed a large fundating mass in the third portion of the duodenum with fresh blood and appeared to be causing narrowing of the lumen. EUS revealed a large circumferential periduodenal hypoechoic mass not involving the pancreas. Origin of mass not identified, but appeared soft and vascular. Pathology of the small bowel periduodenum consistent with dedifferentiated liposarcoma, MDM2 FISH- amplified.
Discussion: The patient was evaluated by medical, radiation, and surgical oncology given the pathology confirming dedifferentiated RPLS, grade two. Therapy includes neoadjuvant radiation prior to surgical intervention. Due to the anemia, hemoglobin levels are monitored often. This case indicates that the rarely diagnosed dedifferentiated RPLS can in fact present as an upper gastrointestinal bleed and not as mass effect. [1]
1. Matthyssens et al., Retroperitoneal liposarcoma: current insights in diagnosis and treatment, Feb. 10 2015
