What is the most common histological type of pancreatic cancer?

Explanation

## Histological Types of Pancreatic Cancer **Key Point:** Ductal adenocarcinoma (PDAC) accounts for approximately 85–90% of all pancreatic malignancies, making it by far the most common type. ### Epidemiology & Frequency | Histological Type | Frequency | 5-Year Survival | Key Features | | --- | --- | --- | --- | | **Ductal adenocarcinoma** | 85–90% | 5–10% | Highly aggressive, early metastasis, poor prognosis | | Acinar cell carcinoma | 1–2% | 20–30% | Low-grade, better prognosis, often incidental | | Neuroendocrine tumor | 1–5% | Variable (10–70%) | Hormone-secreting, slower growth, better outcome | | Mucinous cystic neoplasm | 1–3% | 50–70% (if resected) | Cystic, often borderline/malignant potential | ### Why Ductal Adenocarcinoma Dominates 1. **Origin:** Arises from ductal epithelium, which comprises the majority of pancreatic tissue 2. **Aggressive biology:** Early invasion, perineural spread, rapid metastasis to liver and peritoneum 3. **Poor prognosis:** Median survival ~6–12 months; 5-year survival <10% even with resection **Clinical Pearl:** Most patients with ductal adenocarcinoma present at stage III–IV (locally advanced or metastatic) because early tumors are asymptomatic and located deep in the pancreas. **High-Yield:** When an exam question refers to "pancreatic cancer" without further specification, it is almost always asking about ductal adenocarcinoma. This is the default assumption in clinical practice. ### Other Histological Types (Rarer) - **Acinar cell carcinoma:** Low-grade, often discovered incidentally; better prognosis than PDAC - **Neuroendocrine tumors (PNETs):** Functional (insulinoma, gastrinoma) or non-functional; slower growth; some are benign - **Mucinous cystic neoplasms:** Cystic lesions with malignant potential; often resectable with better outcomes if caught early **Warning:** Do not confuse mucinous cystic neoplasm (a cystic lesion with borderline/malignant potential) with the solid, highly aggressive ductal adenocarcinoma. Cystic lesions have a better prognosis if resected before invasive transformation.