Poorly Differentiated Pancreatic Neuroendocrine Carcinoma
Definition
- Carcinoma of the pancreas showing neuroendocrine differentiation and a high proliferative rate (>20 MF/10 HPF) or extensive necrosis
Alternate/Historical Names
- High grade neuroendocrine carcinoma
- Large cell neuroendocrine carcinoma
- Oat cell carcinoma
- Poorly differentiated endocrine carcinoma
- Small cell carcinoma
Diagnostic Criteria
- Small cell variant resembles small cell carcinomas seen in other organs
- Small cells with scant cytoplasm
- Fine chromatin
- Nuclear molding
- Diffuse pattern of growth
- Numerous mitotic figures (by definition >20/10HPF)
- Abundant necrosis
- Usually positive for synaptophysin and/or chromogranin
- May be focal
- Not required for diagnosis
- Large cell variant
resembles pulmonary large cell neuroendocrine carcinoma
- More prominent nesting pattern
- Moderate amount of amphophilic cytoplasm
- Large nuclei with clumped chromatin and prominent nucleoli
- Numerous mitotic figures (by definition >20/10HPF)
- Positive staining with neuroendocrine markers is required for the diagnosis
Differential Diagnosis
| Large Cell Poorly Differentiated Pancreatic Neuroendocrine Carcinoma | Well Differentiated Pancreatic Neuroendocrine (Islet Cell) Tumor |
|---|---|
| Mitotic rate >20/10 hpf | Mitotic rate not over 20/10 hpf |
| May have extensive necrosis | Lacks extensive necrosis |
| Acinar Cell Carcinoma of the Pancreas | Poorly Differentiated Pancreatic Neuroendocrine (Islet Cell) Tumor |
|---|---|
| Granular PASd+ cytoplasm | PASd negative |
| BCL10, trypsin, chymotrypsin positive | BCL10, trypsin, chymotrypsin negative |
| Stromal fibrosis rare | Frequent fibrotic stroma |
| Synaptophysin and chromogranin positivity <25% in pure tumors, mixed tumors may have more | Synaptophysin or chromogranin positivity widespread, over 25% |
Metastasis from a distant site or direct extension from duodenum
- Must be ruled out clinically
- TTF1
- Stains the vast majority of pulmonary neuroendocrine carcinomas
- Also reported in a small minority of extrapulmonary neuroendocrine carcinomas
- Has not been reported to stain pancreatic neuroendocrine neoplasms but few tested
- Stains the vast majority of pulmonary neuroendocrine carcinomas
Staging
- Same TNM staging as exocrine pancreas
Classification / Lists
Pancreatic Carcinomas
- Acinar cell carcinoma
- Adenosquamous carcinoma
- Colloid carcinoma
- Ductal adenocarcinoma
- Neuroendocrine carcinoma, poorly differentiated
- Well differentiated neuroendocrine (islet cell) tumors
- Hepatoid carcinoma
- Medullary carcinoma
- Micropapillary carcinoma
- Pancreatoblastoma
- Serous cystadenocarcinoma
- Signet ring cell carcinoma
- Undifferentiated carcinoma
- Undifferentiated carcinoma with osteoclast-like giant cells
Pancreatic Endocrine Tumors
- Islet cell hyperplasia / aggregation
- Pancreatic neuroendocrine microadenoma
- Poorly differentiated pancreatic neuroendocrine carcinoma
- Well differentiated pancreatic neuroendocrine (islet cell) tumor
- Mixed acinar-endocrine carcinoma
Bibliography
- Hruban RH, Pitman MB, Klimstra DS. Tumors of the Pancreas, Atlas of Tumor Pathology, AFIP Fourth Series, Fascicle 6, 2007.
- Klimstra DS. Nonductal neoplasms of the pancreas. Mod Pathol. 2007 Feb;20 Suppl 1:S94-112.
- Verbeke CS. Endocrine tumours of the pancreas. Histopathology. 2010 May;56(6):669-82.
Author / Update
Reetesh Pai MD
Robert V Rouse MD
Department of Pathology
Stanford University School of Medicine
Stanford CA 94305-5342
Original posting/updates : 2/1/08, 6/18/10, 1/1/12, 1/16/13
