Laparoscopic pancreaticoduodenectomy for metastatic pancreatic melanoma A case report

Introduction: Pancreatic metastases from other malignant tumors are an uncommon clinical condition and account for approximately 2% of all pancreatic malignancies. The most common primary malignancy that metastasizes to pancreas is renal cell cancer. We reported a rare clinical case of metastatic melanoma to pancreas who underwent a successful laparoscopic pancreaticoduodenectomy (LPD) at our department. Case presentation: A 54-year-old Chinese man complaining an unexplained jaundice was found to have a pancreatic mass and he was diagnosed with cutaneous melanoma (CM) 6 years ago. Contrast-enhanced computed tomography (CECT) revealed a solid hypovascular mass measuring about 3.1 x 2.4 cm localized at the junction of pancreatic head and uncinate process, which compressed the lower common bile duct resulting in expansion of the upstream bile ducts. We performed an LPD and regional lymphadenectomy on this patient. This patient was discharged home on postoperative day 19. Postoperative pathological results revealed a malignant melanoma with negative margins. Immunohistochemical (IHC) findings also suggested a malignant pancreatic tumor accompanied by necrosis and pigmentation, which confirmed the pathological diagnosis. Immunoreactivity was strongly positive for anti-S-100 protein (+++) and positive for anti-Vimentin (+). The cancer cells were negative for CEA, CK8/18, P53, Violin, CK19, SMA with Ki-67 over 40%. So this pancreatic mass was proved to be a metastatic pancreatic melanoma from the primary cutaneous lesion. After LPD, this patient was followed up by readmission to hospital every 2 month in the first half year. The serum bilirubin and tumor markers such as CA199 were normal. CECT and did not find any newly developed neoplasm at the pancreas or metastasis at other organs. At the last follow-up at 6 months after LPD, the patient's general condition was acceptable and the physical examination and imaging studies revealed no significant findings of melanoma. Conclusion: Metastatic pancreatic tumors are often associated with well-defined margins, tumor necrosis, enhancement, and distant metastases without pancreatic duct dilatation and parenchymal atrophy. As the most common type of metastatic pancreatic tumor, renal cell cancers tend to have higher attenuation values than that of primary pancreatic cancer, while they had similar attenuation values on the portal phase. Primary pancreatic cancer was always associated with an elevated CA199, total bilirubin, and fasting plasma glucose levels. Surgical resection for metastases to pancreas should be aggressively considered in selected patients due to its unique value of providing palliation and a chance to cure. For patients with unresectable lesions, new therapeutic protocols should be recommended such as the combination of BRAF with MEK inhibitor and PD-1 blocker with or without ipilimumab.