Primary duodenal dedifferentiated liposarcoma: A case report and literature review

Abstract

Background: Dedifferentiated liposarcoma (DDLPS) is an extremely rare neoplasm that exhibits various morphologies. The tumor is characterized by immunoreactivity to MDM2 and CDK4 and can be confirmed by detecting MDM2 amplification via fluorescence in situ hybridization (FISH). Herein, we report an unusual case of DDLPS arising from the duodenum.

Case summary: A 64-year-old man presented with repeated abdominal pain and weight loss. Radiologic studies revealed a mass of the duodenum involving the pancreas. The patient was treated with pylorus-preserving pancreaticoduodenectomy. Histologically, the tumor showed a high-grade sarcoma. Immunohistochemistry demonstrated that the tumor cells were positive for MDM2 and CDK4 expression. MDM2 amplification was detected via FISH, leading to the final diagnosis of DDLPS. Following surgery, the patient was treated in the intensive care unit due to peritonitis, and died 60 d after surgery.

Conclusion: To the best of the authors' knowledge, this is the first case of primary duodenal DDLPS in Korea and the third case in the English-language literature. Care must be taken not to misdiagnose DDLPS as another high-grade tumor. Liposarcoma should be in the differential diagnosis list.

Keywords: Case report; Duodenum; Immunohistochemistry; Liposarcoma; Primary; Small bowel.

Figure 1

Radiologic findings. A, B: Abdominal computed tomography scan demonstrated a heterogeneously enhanced mass in the pancreaticoduodenal groove with duodenal obstruction.

Figure 2

Features of tumor cells. A: The tumor was located in the submucosal layer of the duodenum (Hematoxylin-and-eosin stain, ×20); B: At a higher magnification, undifferentiated tumor cells were shown to have marked nuclear atypia with brisk mitotic activity (Hematoxylin-and-eosin stain, ×200); C: Immunohistochemistry revealed positivity for MDM2 in the tumor cells (Immunohistochemistry, ×200); D: MDM2 amplification was detected by MDM2/CEN12 fluorescence in situ hybridization assay (MDM2-green signals, CEN12-red signals, ×1000).