A duodenal gastrointestinal stromal tumor mimicking a pancreatic neuroendocrine tumor: a case report.

BACKGROUND: Duodenal gastrointestinal stromal tumors are rare. If tumor growth is extraluminal and involves the head of the pancreas, the diagnosis of a duodenal gastrointestinal stromal tumor is difficult. CASE PRESENTATION: A 44-year-old Japanese woman was referred to our hospital with anemia. An enhanced computed tomography scan showed a hypervascular mass 30 mm in diameter, but the origin of the tumor, either the duodenum or the head of the pancreas, was unclear. Upper gastrointestinal endoscopy revealed bulging accompanied by erosion and redness in part of the duodenal bulb. Mucosal biopsy was not diagnostic. Endoscopic ultrasound fine-needle aspiration was difficult to perform because a pulsating blood vessel was present in the region to be punctured. These findings led to a diagnosis of pancreatic neuroendocrine tumor invasion to the duodenum. The patient underwent pancreaticoduodenectomy. Histologically, the tumor was made up of spindle-shaped cells immunohistochemically positive for c-Kit and CD34. The tumor was ultimately diagnosed as a duodenal gastrointestinal stromal tumor. CONCLUSION: Extraluminal duodenal gastrointestinal stromal tumors are rare and mimic pancreatic neuroendocrine tumors. Endoscopic ultrasound fine-needle aspiration is useful for preoperative diagnosis, but it is not possible in some cases. Intraoperative diagnosis based on a completely resected specimen of the tumor may be useful for modifying the surgical technique.

A liver metastasis 7 years after resection of a low-risk duodenal gastrointestinal stromal tumor.

Duodenal gastrointestinal stromal tumors (dGISTs) are rare, and a lack of consensus exists regarding their treatment, particularly for recurrent disease. We herein report a rare case of liver metastasis 7 years after resection of a low-risk duodenal gastrointestinal stromal tumor. A 45-year-old woman revealed positive fecal occult blood. Upper gastrointestinal endoscopy revealed a submucosal duodenal tumor with ulceration and oozing on the apex. Endoscopic ultrasound showed a hypoechoic mass originating in the submucosa. Contrast-enhanced abdominal computed tomography (CT) revealed a 30-mm hyper-vascular tumor in the duodenal bulb. The patient underwent partial resection of the duodenal bulb with distal gastrectomy, followed by Roux-en-Y reconstruction. Histopathological evaluation revealed a tumor comprised of spindle-shaped cells including 5 mitotic figures per 50 high-power fields. Immunohistochemical evaluation indicated that the tumor cells were positive for c-Kit and CD34 expression. The tumor was diagnosed as low-risk dGIST. Postoperative follow-up was continued, and 7 years later, CT revealed a 39-mm enhanced tumor in liver segment 4. The tumor was diagnosed as a metastatic liver tumor, and the patient underwent S4 partial hepatectomy. As a result of histological and immunohistochemical analysis, the tumor was diagnosed as a liver metastasis from dGIST. The patient has been receiving oral imatinib 400 mg daily and remains free of disease 5 years after her last surgery. Low-risk dGIST can metastasize relatively long after surgery. However, an excellent long-term prognosis may be achieved by combining complete resection and imatinib therapy in patients with recurrent liver metastases.

Alpha-fetoprotein-producing Colon Carcinoma with Rapidly Increasing Liver Metastases That Resulted in Death: A Case Report.

Alpha-fetoprotein (AFP) has been widely used as a tumor marker for detecting hepatocellular carcinoma and yolk sac tumors. Recently, cases of gastrointestinal cancer with elevated serum AFP levels have been reported. However, AFP-producing colon cancer is considered rarer than other AFP-producing gastrointestinal cancers. In this study, we report on a case of a 47-year-old woman who was diagnosed with sigmoid colon cancer and underwent sigmoidectomy and lymph node dissection. Postoperative adjuvant chemotherapy (AC) was performed after the curative surgery. After the seventh course of AC, multiple liver masses and enlarged systemic lymph nodes were detected; these were later diagnosed as liver metastases from sigmoid colon cancer. Laboratory examination revealed high AFP levels (14,657.8 ng/mL). After confirming the recurrence, her condition worsened rapidly, and she eventually died 8 months after the operation. Autopsy and histopathological findings showed that the liver mass was positive for AFP staining, but the sigmoid colon cancer tissue was not. We then determined that liver metastases of the colon cancer were more likely than germ cell carcinoma according to the clinical course and pathological findings. We assumed that colon cancer cells can rapidly expand by dedifferentiation, and we diagnosed AFP-producing colon cancer with liver metastases. Despite curative surgery and AC for AFP-producing colon cancer, the patient died of liver and systemic lymph node metastases.