title: Primary carcinoid tumor of the common hepatic duct: A rare case with immunohistochemical and molecular findings.
abstract: We report immunohistochemical (IHC) and molecular findings in a rare case of a carcinoid tumor of the extrahepatic bile ducts in a 33-year-old woman, who presented with a 3.9x2.8x2.6 cm mass within the right and common hepatic ducts. She underwent surgery and a carcinoid tumor was identified. This lesion is of interest because in addition to the morphological and cytological features of a typical carcinoid, it demonstrated a distinct pleomorphic area immunoreactive for gastrin. By molecular analysis, loss of heterozygosity (LOH) with opposite allelic patterns between the gastrin-positive and gastrin-negative areas of the tumor was identified. The molecular studies for LOH along with the morphology and IHC profiling suggest that this second population of gastrin-positive carcinoid cells may represent a new clone within the carcinoid tumor with differentiation toward gastrin production or may represent the next step in the carcinogenic process with a gradual emergence of a more aggressive clone.
authors.affiliation: Department of Pathology and Laboratory Medicine, Hartford Hospital, Hartford, CT, USA.
authors.forename: Saverio
authors.initials: S
authors.lastname: Ligato
authors.forename: Wieslaw
authors.initials: W
authors.lastname: Furmaga
authors.forename: Richard W
authors.initials: RW
authors.lastname: Cartun
authors.forename: David
authors.initials: D
authors.lastname: Hull
authors.forename: Gregory J
authors.initials: GJ
authors.lastname: Tsongalis
mesh_terms: D000328:Adult; D000483:Alleles; D001650:Bile Duct Neoplasms / Q000235:genetics* / Q000276:immunology*; D002276:Carcinoid Tumor / Q000235:genetics* / Q000276:immunology*; D002471:Cell Transformation, Neoplastic; D005260:Female; D006500:Hepatic Duct, Common / Q000473:pathology*; D006801:Humans; D007150:Immunohistochemistry; D019656:Loss of Heterozygosity