Tumor-to-tumor metastasis: an extremely rare combination with renal cell carcinoma as the donor and a pancreatic neuroendocrine tumor as the recipient.

BACKGROUND: Tumor-to-tumor metastasis is a rare phenomenon in which primary tumor cells metastasize hematogenously into another tumor. Herein, we report an extremely rare case of a renal cell carcinoma metastasis into a pancreatic neuroendocrine tumor exhibiting a tumor-to-tumor metastasis. Ours is the third reported case worldwide. CASE PRESENTATION: The patient, a 72-year-old male, was referred to our hospital for further examination and treatment due to high levels of prostate-specific antigen. A left renal tumor and pancreatic head tumor were revealed incidentally on screening computed tomography. There were suspected to be a renal cell carcinoma and primary pancreatic neuroendocrine tumor or pancreatic metastasis from the renal cell carcinoma according to preoperative examination. The left nephrectomy and subtotal stomach-preserving pancreaticoduodenectomy were performed because of the pancreatic tumor indicated for operation in either case of diagnosis. Postoperative pathological examination showed a diagnosis of clear cell renal cell carcinoma for the left renal tumor. The pancreatic tumor was diagnosed with clear cell renal cell carcinoma metastasis into the pancreatic neuroendocrine tumor, that is to say tumor-to-tumor metastasis. CONCLUSION: In some cases, conservative approach is selected for pancreatic neuroendocrine tumor patients who meet some requirements. However, if such patients exhibit tumor-to-tumor metastasis which combines with renal cell carcinoma and pancreatic neuroendocrine tumor as this case, conservative approach leads to progression of renal cell carcinoma. Therefore, conceiving the possibility of tumor-to-tumor metastasis, it is necessary to carefully choose a treatment plan for pancreatic neuroendocrine tumor patients associated with renal cell carcinoma, not easily choosing conservative approach.

A case with massive hemobilia long-term after internal drainage surgery for congenital biliary dilation.

BACKGROUND: Currently, there is an unwavering consensus that the standard surgery for congenital biliary dilation (CBD) is extrahepatic bile duct resection and choledochojejunostomy. However, decades prior, choledochocyst-gastrointestinal anastomosis without extrahepatic bile duct resection (internal drainage surgery, IDS) was preferred for CBD because of its simplicity. Currently, there is almost no chance of a surgeon encountering a patient who has undergone old-fashioned IDS, which has been completely obsolete due to the risk of carcinogenesis from the remaining bile duct. Moreover, the pathological condition long after IDS is unclear. Herein, we report a case of life-threatening bile duct bleeding as well as carcinoma of the bile duct 62 years after IDS in a patient with CBD. CASE PRESENTATION: An 82-year-old Japanese woman with hemorrhagic shock due to gastrointestinal bleeding was transferred to our hospital. She had a medical history of unspecified surgery for CBD at the age of 20. Based on imaging findings and an understanding of the historical transition of the surgical procedure for CBD, the cause of gastrointestinal bleeding was determined to be rupture of the pseudoaneurysm of the dilated bile duct that remained after IDS. Hemostasis was successfully performed by transcatheter arterial embolization (TAE) in an emergency setting. Then, elective surgery for extrahepatic bile duct resection and choledochojejunostomy was performed to prevent rebleeding. Pathological examination revealed severely and chronically inflamed mucosa of the bile duct. Additionally, cholangiocarcinoma (Tis, N0, M0, pStage 0) was incidentally revealed. CONCLUSION: It has been indicated that not only carcinogenesis, but also a risk of life-threatening bleeding exists due to long-lasting chronic inflammation to the remnant bile duct after IDS for CBD. Additionally, both knowledge of which CBD operation was performed, and an accurate clinical history are important for the diagnosis of hemobilia.

Exosome-encapsulated microRNA-4525, microRNA-451a and microRNA-21 in portal vein blood is a high-sensitive liquid biomarker for the selection of high-risk pancreatic ductal adenocarcinoma patients.

BACKGROUND: Pancreatic ductal adenocarcinoma (PDAC) is a lethal malignancy with poor prognosis. This is due to late diagnosis and lack of reliable prognostic biomarkers. In this study, we focused on exosomal microRNA (miRNA) in portal vein blood (PVB) as a potential biomarker to identify patients at high-risk for recurrence and poor postoperative outcome. METHODS: Exosomal miR-4525, miR-451a and miR-21 expressions were assessed using PVB and peripheral blood (PB) collected from 55 PDAC patients during curative pancreatectomy. Correlation between the miRNA expressions and clinical outcomes, and target genes expressions was investigated. RESULTS: Exosomal miR-4525, miR-451a and miR-21 levels were upregulated in PVB, which were higher than those in the PB. High expression of miR-4525, miR-451a and miR-21 in PVB was associated with recurrence with a higher sensitivity, specificity, and accuracy than that in PB. Cox regression analysis showed miR-4525, miR-451a and miR-21 levels in PVB were independent prognostic factors for overall survival and disease-free survival. There was a negative correlation between the expressions of miR-4525 and MEN1 mRNA, miR-451a and CAB39 mRNA, and t miR-21 and PDCD4 mRNA. CONCLUSIONS: miR-4525, miR-451a and miR-21 in PVB are potential biomarkers identifying patients at high-risk for recurrence and poor survival in resected PDAC patients.

Usefulness of exosome-encapsulated microRNA-451a as a minimally invasive biomarker for prediction of recurrence and prognosis in pancreatic ductal adenocarcinoma.

BACKGROUND: MicroRNAs (miRNAs) encapsulated in the exosomes of plasma is of interest as stable and minimally invasive biomarkers for recurrence and prognosis in cancer patients. The aim of this study was to clarify the predictive and prognostic value of plasma exosomal microRNA-451a (miR-451a) in patients with pancreatic ductal adenocarcinoma (PDAC). METHODS: Microarray-based expression profiling of miRNAs derived from exosomes in the plasma of six PDAC patients with UICC stage II was employed to identify a biomarker to distinguish between patients with and without recurrence. For validation analysis, plasma exosome samples of other 50 PDAC patients were measured by TaqMan MicroRNA assays. RESULTS: In the miRNA microarray analyses, miR-451a showed the highest upregulation in the stage II patients who showed recurrence after surgery. In the relationship to pathological factors, exosomal miR-451a showed a significant association with tumor size and stage. The overall survival (OS) and disease-free survival rates (DFS) of the high exosomal miR-451a patients were significantly worse than those of the low miR-451a patients. In Cox proportional hazards model analysis, exsomal miR-451a showed significance to OS and DFS. CONCLUSIONS: Plasma exosomal miR-451a levels may be a useful minimally invasive biomarker for the prediction of recurrence and prognosis in PDAC patients.