Two Case Reports of Resectable Cancer in the Remnant Pancreas after Pancreatectomy for Invasive Ductal Carcinoma of the Pancreas

Abstract

Pancreatic cancer has an extremely poor prognosis. There are several reports on resectable cancer in the remnant pancreas after pancreatectomy; however, few have compared K-ras mutation patterns to clarify recurrent or second primary cancers. Here, we report on 2 cases of cancer in the remnant pancreas after total pancreatectomy for invasive ductal carcinoma. Case 1 is a 56-year-old man who underwent pancreaticoduodenectomy for cancer of the pancreatic head. However, serum carbohydrate antigen (CA19-9) was again elevated 23 months later. A tumor in the pancreatic tail was detected on abdominal computed tomography (CT), and total pancreatectomy was performed. Histologic examination of the tumors from both operations revealed moderately differentiated adenocarcinoma, and the surgical margins of both resected specimens were free of cancerous cells. The K-ras gene mutation was detected at codon 12V of exon 1 in both cancers. Case 2 is a 72-year-old woman who underwent distal pancreatectomy for cancer of the pancreatic body. However, serum CA19-9 was again elevated 4 years postoperatively. A tumor of the pancreatic head was detected on abdominal CT, and total pancreatectomy was performed. Histologic examination of the first and second tumors revealed poorly and moderately differentiated adenocarcinomas, respectively. The surgical margins of both resected specimens were free of cancerous cells. The K-ras gene mutation was detected at codon 12D of exon 1 in both cancers. These patients with rare pancreatic cancers both had metachronous carcinogenesis in the remnant pancreas.