Low microvessel density is an unfavorable histoprognostic factor in pancreatic endocrine tumors.
OBJECTIVE
In many malignant tumors, intratumoral microvascular density (MVD) has been suggested to be a prognostic parameter. We aimed to provide a quantitative evaluation of intratumoral microvascular density in a large series of resected endocrine tumors of the pancreas and to evaluate the potential prognostic significance of this parameter.


METHODS
Eighty-two tumors from 77 patients have been studied. MVD was evaluated by 2 observers after CD34 immunostaining and correlated with the following parameters: WHO classification, hormonal profile, tumor size, vascular endothelial growth factor expression, occurrence of metastasis, duration of survival.


RESULTS
MVD ranged from 5 to 92 vessels/field. MVD was significantly higher in well-differentiated benign endocrine tumors than in tumors of uncertain behavior and in carcinomas. No close correlation was found between MVD and the hormonal profile. MVD was significantly higher in tumors characterized by the following histoprognostic parameters: size <2 cm, proliferation index <2%, no evidence of metastasis. No close correlation was observed between MVD and VEGF expression. Finally, a MVD <30 vessels/field was associated with the occurrence of metastasis in tumors <2 cm and/or with a proliferation index <2% and with a significantly shorter survival after surgery.


CONCLUSIONS
The quantitative analysis of microvessel density in pancreatic endocrine tumors may identify patients who, despite favorable conventional histoprognostic factors, are at risk of unfavorable evolution.
D001160:Arterioles / Q000473:pathology; D002455:Cell Division; D016228:Endothelial Growth Factors / Q000378:metabolism; D006801:Humans; D016130:Immunophenotyping; D036341:Intercellular Signaling Peptides and Proteins / Q000378:metabolism; D008222:Lymphokines / Q000378:metabolism; D009389:Neovascularization, Pathologic / Q000401:mortality* / Q000473:pathology*; D010187:Pancreatic Hormones / Q000378:metabolism; D010190:Pancreatic Neoplasms / Q000098:blood supply / Q000145:classification / Q000401:mortality* / Q000556:secondary*; D011237:Predictive Value of Tests; D011379:Prognosis; D012189:Retrospective Studies; D015996:Survival Rate; D042461:Vascular Endothelial Growth Factor A; D042442:Vascular Endothelial Growth Factors; D014944:World Health Organization
D016228:Endothelial Growth Factors; D036341:Intercellular Signaling Peptides and Proteins; D008222:Lymphokines; D010187:Pancreatic Hormones; D042461:Vascular Endothelial Growth Factor A; D042442:Vascular Endothelial Growth Factors