Complete resection of a huge pancreatic undifferentiated carcinoma with osteoclast-like giant cells.

Pancreatic undifferentiated carcinoma with osteoclast-like giant cells (PUC-OGC) is a rare neoplasm. We report a case of rapidly advancing PUC-OGC. A 54-year-old man had elevated tumor marker levels. Abdominal computed tomography showed a cystic mass in the body and tail of the pancreas, which infiltrated adjacent organs. The tumor exhibited rapid growth (doubling time: 39 days) but no metastases. We diagnosed PUC-OGC clinically and excised the pancreatic body and tail along with the spleen, left kidney, adrenal gland, and transverse colon. Pathological diagnosis showed histology consistent with PUC-OGC and a negative margin without nodal involvement despite the tumor being 28 cm in maximum diameter and having invaded the left kidney. The patient survived a year with a recurrence of liver metastasis after the initial surgery due to the partial hepatectomy and chemotherapy. Complete resection might be a good strategy to cure PUC-OGC in this case.