Editorial orientation provided by MedAPI — not part of the coding instruction.
C25 encompasses primary malignant neoplasms of the pancreas, subdivided by pancreatic site, including the head, body, tail, pancreatic duct, endocrine pancreas, overlapping sites, and unspecified sites.
Common Histologies
- Pancreatic ductal adenocarcinoma is the predominant histology and most often arises in the pancreatic head.
- Less common exocrine malignancies include acinar cell carcinoma, adenosquamous carcinoma, and pancreatoblastoma.
- Pancreatic neuroendocrine tumors arise from the endocrine pancreas and differ substantially from ductal adenocarcinoma in biology, staging, prognosis, and treatment.
Common Symptoms
Presentation varies with tumor location and extent:
- Painless jaundice, dark urine, pale stools, or pruritus, particularly with tumors in the pancreatic head (R17)
- Epigastric or back pain (R10.13)
- Unintentional weight loss, anorexia, nausea, or fatigue (R63.4)
- New-onset or worsening diabetes (E11.65)
- Acute pancreatitis or biliary obstruction (K85.90)
- Steatorrhea and other manifestations of exocrine pancreatic insufficiency (K86.81)
- Hormone-related syndromes in functional neuroendocrine tumors (E34.2), such as hypoglycemia (E16.2), peptic ulcer disease (K27.9), or secretory diarrhea (E34.1)
Diagnosis
Evaluation commonly includes pancreas-protocol multiphasic CT or MRI/MRCP. Endoscopic ultrasonography with tissue sampling is frequently used when histologic confirmation is needed. ERCP may be used selectively for biliary decompression and ductal sampling.
Serum CA 19-9 can support assessment and longitudinal monitoring of pancreatic adenocarcinoma but is not sufficiently sensitive or specific for screening or diagnosis by itself. Chromogranin A and syndrome-specific hormone testing may be considered for neuroendocrine tumors, with important limitations.
Staging
Staging evaluates:
- Primary tumor size and local extension
- Involvement of major vessels and adjacent structures
- Regional lymph-node disease
- Distant metastases, commonly involving the liver, peritoneum, or lungs
For pancreatic ductal adenocarcinoma, clinical management also uses resectability categories such as resectable, borderline resectable, locally advanced unresectable, and metastatic. Pancreatic neuroendocrine tumors use distinct staging and grading frameworks, including mitotic rate and Ki-67 proliferation index.
Molecular Markers
Relevant testing may include:
- Germline testing for inherited susceptibility genes such as BRCA1, BRCA2, PALB2, ATM, and mismatch-repair genes
- Tumor testing for MSI-high/mismatch-repair deficiency, NTRK fusions, KRAS alterations, and other potentially actionable findings
- Somatic or germline homologous-recombination repair alterations that may influence platinum or targeted-therapy selection
- For neuroendocrine tumors, pathologic differentiation and Ki-67 index are central to classification; somatostatin-receptor imaging may guide therapy
Common Treatments
Treatment depends on histology, stage, resectability, performance status, and molecular findings.
- Surgical resection may include pancreaticoduodenectomy for head lesions or distal pancreatectomy for body or tail lesions.
- Perioperative or systemic chemotherapy is commonly used for pancreatic ductal adenocarcinoma.
- Radiation therapy may be considered in selected localized or locally advanced cases.
- Biliary stenting, pain management, nutritional support, pancreatic enzyme replacement, and diabetes management are important supportive measures.
- Neuroendocrine tumors may be treated with surgery, somatostatin analogues, targeted agents, peptide receptor radionuclide therapy, liver-directed therapy, or cytotoxic chemotherapy, depending on grade and extent.
Scope Note
C25 identifies a primary malignant neoplasm of the pancreas and, through its child codes, the documented pancreatic subsite. It does not by itself encode histologic type, tumor grade, TNM stage, resectability, molecular profile, functional hormone status, or treatment response. Metastases from a pancreatic primary require separate secondary-neoplasm coding when documented; a malignancy metastatic to the pancreas is not classified as a primary C25 neoplasm. Associated conditions such as exocrine pancreatic insufficiency may require separate coding when applicable.