• Pancreatic Duct Stenosis Secondary to Small Endocrine Neoplasms: A Manifestation ot Serotonin Production?

    Radiology:Volume257:Number 1-October 2010

    Pancreatic Duct Stenosis Secondary to Small Endocrine Neoplasms: A Manifestation ot Serotonin Production?

    Chanjuan Shi, MD, PhD Stanley S. Siegelman, MD Satomi Kawamoto, MD Christopher L. Wolfgang, MD, PhD Richard D. Schulick, MD Anirban Maitra, MBBS Ralph H. Hruban, MD

    Purpose: To determine if serotonin production by pancreatic en­docrine neoplasms" is associated with the pancreatic duct stenosis seen in patients with stenosis that is out of pro­portion to the size of the tumors seen on computed tomo­graphic images.

    Materials and methods: Institutional approval was obtained for this HIPAA-compliant study. Informed consent was waived. Clinical and radio­logic findings in six patients were reviewed. Gross and histologic findings in the resected pancreata were also assessed. Formalin-fixed paraffin-embedded tumor sec­tions were immunolabeled with antibodies to serotonin. Tissue microarrays constructed from 47 pancreatic en­docrine neoplasms from the institutional tissue bank served as controls. Histologic and serotonin immuno­reactivity findings were compared between the two groups. The Fisher exact test was used to compare serotonin immunoreactivity.

    Results: Only one of the six study patients had a large dominant tumor (4 cm in the pancreatic head). All others were 2.5 cm or smaller. Four of the six pancreatic endocrine neoplasms with associated pancreatic duct stricture had prominent stromal fibrosis. Serotonin immunoreactivity was present in five (83%) patients, and this labeling was strong and diffuse in the four patients with prominent fibrosis. By contrast, stromal fibrosis was minimal in the nonimmunoreactive case. Only three (6%) of the 47 con­trol pancreatic endocrine neoplasms were immunoreac-tive for serotonin (P < .01, Fisher exact test).

    Conclusion: These data suggest that serotonin produced by pancreatic endocrine neoplasms may be associated with local fibrosis and stenosis of the pancreatic duct. Clinicians should be aware that small pancreatic endocrine neoplasms can pro­duce pancreatic duct stenosis resulting in ductal dilatation and/or upstream pancreatic atrophy out of proportion to the size of the tumor.