A yolk sac tumor of the pancreas and derived xenograft model effectively responded to VIP chemotherapy.

Background: Yolk sac tumors (YSTs) of the pancreas are extremely rare, and no drug responsiveness data are available regarding YSTs.

Methods: We report a pancreatic YST in a 70-year-old woman, and its chemotherapeutic responsiveness based on clinical records and evaluation of a patient-derived xenograft (PDX) line of the YST.

Results: The YST was an 11-cm, solid mass located in the pancreatic tail. Histologically, the tumor showed medullary proliferation of tumor cells, with a variety of growth patterns including microcystic/reticular, endodermal sinus, and hepatoid patterns. Immunohistochemically, the tumor cells were positive for Sall4, glypican-3, and alpha-fetoprotein. We administered VIP (etoposide, ifosfamide, cisplatin) chemotherapy for a recurrent liver tumor, and obtained complete pathological remission. A drug-response assay using the PDX line from this YST revealed that both VIP and gemcitabine effectively inhibit tumor growth.

Conclusions: These results suggest that differential diagnosis of YST from adenocarcinoma is important for selecting appropriate chemotherapy.