title: Cellular composition and anatomic distribution in nonfunctioning pancreatic endocrine tumors: immunohistochemical study of 30 cases.
abstract: OBJECTIVE
  To investigate the cytological pattern and distribution in nonfunctioning pancreatic endocrine tumors.
  
  
  METHODS
  Using labeled streptavidin-biotin (LSAB), immunohistochemical staining for insulin, glucagon, somatostatin, pancreatic polypeptide and gastrin was performed on 30 nonfunctioning pancreatic endocrine tumors from 30 patients. The cellular composition and anatomic distribution in these tumors were analyzed.
  
  
  RESULTS
  Of 30 tumor tissues, 22 (73.3%) were found to contain cells immunoreactive to 1-4 kinds of peptide hormones; 17 (56.7%) showed positive staining for more than one peptide and up to 4 peptides; and 8 (26.7%) showed negative immunoreaction to all antiserum applied. No tumor was found to contain immunoreactive gastrin. Among 17 multihormonal tumors, 4 contained 2 kinds of peptide hormones, 8 had 3 kinds, and 5 harbored 4 kinds of peptide hormones. In addition, the difference in the number and type of positive endocrine cells between the tumors arising from the head of the pancreas and those arising from the body and tail of the pancreas were statistically significant (P < 0.05).
  
  
  CONCLUSIONS
  Immunohistochemically, the high positive rate to peptide hormones suggests that the nonfunctioning pancreatic endocrine tumors are actually not nonfunctioning; they are asymptomatic pancreatic endocrine tumors. Moreover, an uneven distribution of positive endocrine cells in the nonfunctioning pancreas endocrine tumors within the pancreas was identified.
authors.affiliation: Department of Surgery, First Affiliated Hospital, China Medical University, Shenyang, China.
authors.forename: X
authors.initials: X
authors.lastname: Zheng
authors.forename: K
authors.initials: K
authors.lastname: Guo
authors.forename: Y
authors.initials: Y
authors.lastname: Tian
authors.forename: J
authors.initials: J
authors.lastname: Li
authors.forename: R
authors.initials: R
authors.lastname: Guo
authors.forename: Y
authors.initials: Y
authors.lastname: Zhan
authors.forename: M
authors.initials: M
authors.lastname: Song
authors.forename: K
authors.initials: K
authors.lastname: Shen
mesh_terms: D007516:Adenoma, Islet Cell / Q000737:chemistry* / Q000145:classification; D000293:Adolescent; D000328:Adult; D000368:Aged; D018273:Carcinoma, Islet Cell / Q000737:chemistry / Q000145:classification; D002648:Child; D005260:Female; D005934:Glucagon / Q000032:analysis*; D006801:Humans; D007150:Immunohistochemistry; D007328:Insulin / Q000032:analysis*; D008297:Male; D008875:Middle Aged; D010190:Pancreatic Neoplasms / Q000737:chemistry* / Q000145:classification; D013004:Somatostatin / Q000032:analysis
chemical_list: D007328:Insulin; D013004:Somatostatin; D005934:Glucagon