Conversion surgery for undifferentiated carcinoma with osteoclast-like giant cells of the pancreas: a case report

BACKGROUND: Undifferentiated carcinoma with osteoclast-like giant cells (UCOGCs) is a rare subtype of pancreatic cancer (PC), and its clinicopathological characteristics are still unclear. Herein, we report a case of initially unresectable UCOGC that was successfully resected after FOLFIRINOX therapy. CASE PRESENTATION: A 63-year-old man was referred to us for evaluation of a pancreatic mass detected by computed tomography (CT) during a medical checkup. Computed tomography showed a 7.5-cm tumor located in the pancreatic head and body, which involved the common hepatic artery (CHA), gastroduodenal artery (GDA), and main portal vein (PV) with tumor thrombus. UCOGC was suspected by endoscopic ultrasonography-guided fine needle aspiration, and the patient was diagnosed with unresectable locally advanced pancreatic cancer. After ten cycles of FOLFIRINOX, the tumor size decreased to 3 cm and the tumor thrombus in the main portal trunk had disappeared in the follow-up CT scan. However, the patient experienced severe adverse drug reactions, including neutropenia and liver dysfunction. Therefore, we performed pancreatoduodenectomy with portal vein resection. The pathological diagnosis was UCOGC with a negative tumor margin. He was treated with FOLFIRINOX, and remains recurrence-free for 6 months after surgery. CONCLUSIONS: We experienced a case undergoing conversion surgery for unresectable UCOGC, which resulted in R0 resection. FOLFIRINOX could be a possible regimen to achieve conversion surgery for UCOGC.