Benign Islet Cells Within Peripancreatic Lymph Nodes: A Potential Diagnostic Pitfall

Area of Science:

• Surgical Pathology
• Endocrinology
• Oncology

Background:

• Epithelial cells in lymph nodes often suggest metastatic malignancy.
• Non-neoplastic epithelial cells can rarely appear in lymph nodes due to displacement or migration.
• Misdiagnosis of benign cells as malignancy poses a significant diagnostic challenge.

Observation:

• Two cases presented benign pancreatic islet cells within peripancreatic lymph nodes.
• These findings were incidental in pancreatic resections for intraductal papillary mucinous neoplasms.
• Associated fibrosis and chronic pancreatitis were noted, suggesting mechanical displacement.

Findings:

• Immunohistochemistry confirmed the presence of both insulin and glucagon-expressing cells.
• The cellular distribution mimicked normal pancreatic islet architecture.
• Absence of neuroendocrine tumor in the pancreatic resection specimen supported benignity.

Implications:

• This phenomenon can be mistaken for metastatic well-differentiated neuroendocrine tumor.
• Accurate diagnosis relies on recognizing benign islet cell morphology and immunohistochemical profiles.
• Understanding these rare findings is crucial for surgical pathologists to avoid overdiagnosis.