Pancreatic duct stenosis secondary to small endocrine neoplasms: a manifestation of serotonin production?
OBJECTIVE
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.


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 immunoreactive for serotonin (P < .01, Fisher exact test).


CONCLUSIONS
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.
Shi
Chanjuan
C
Department of Pathology, Sol Goldman Pancreatic Cancer Research Center, Johns Hopkins Medical Institutions, Weinberg 2242, Baltimore, MD 21231, USA.
Siegelman
Stanley S
SS
Kawamoto
Satomi
S
Wolfgang
Christopher L
CL
Schulick
Richard D
RD
Maitra
Anirban
A
Hruban
Ralph H
RH
D000328:Adult; D003251:Constriction, Pathologic / Q000000981:diagnostic imaging / Q000209:etiology / Q000473:pathology; D003287:Contrast Media; D005260:Female; D005355:Fibrosis / Q000000981:diagnostic imaging / Q000473:pathology; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D008875:Middle Aged; D010182:Pancreatic Diseases / Q000000981:diagnostic imaging* / Q000209:etiology* / Q000473:pathology; D010183:Pancreatic Ducts / Q000000981:diagnostic imaging / Q000473:pathology*; D010190:Pancreatic Neoplasms / Q000000981:diagnostic imaging / Q000378:metabolism*; D012701:Serotonin / Q000378:metabolism*; D014057:Tomography, X-Ray Computed
D003287:Contrast Media; D012701:Serotonin