Most common tumour of pancreas is
**Core Concept**
The question is testing the student's knowledge of the most common pancreatic tumor, which is typically a type of epithelial neoplasm. The pancreas is a complex organ with both exocrine and endocrine functions, and its tumors can be classified based on their origin from either the ductal epithelium or the acinar cells.
**Why the Correct Answer is Right**
The correct answer is pancreatic adenocarcinoma, which arises from the ductal epithelium of the pancreas. This type of tumor accounts for about 85-90% of all pancreatic cancers. The pathogenesis of pancreatic adenocarcinoma is thought to involve a combination of genetic and environmental factors, including mutations in the KRAS, TP53, and SMAD4 genes. These mutations lead to the activation of various signaling pathways, including the Wnt/β-catenin pathway, which promotes cell proliferation and survival.
**Why Each Wrong Option is Incorrect**
**Option A:** Pancreatic neuroendocrine tumors (PNETs) are less common than pancreatic adenocarcinoma, and they arise from the endocrine cells of the pancreas, such as the alpha, beta, or delta cells.
**Option B:** Pancreatic cysts are benign fluid-filled structures that can occur in the pancreas, but they are not considered tumors.
**Option C:** Acinar cell carcinoma is a rare type of pancreatic tumor that arises from the acinar cells of the pancreas, accounting for less than 5% of all pancreatic cancers.
**Clinical Pearl / High-Yield Fact**
Pancreatic adenocarcinoma is often diagnosed at a late stage, which is associated with a poor prognosis. The use of imaging modalities such as CT or MRI is essential for the early detection and staging of this tumor.
**Correct Answer: D. Pancreatic adenocarcinoma**