title: Criteria for malignancy in gastrointestinal endocrine tumors.
abstract: In contrast with the large amount of data generated from endocrine tumors of the pancreas, sparse and mostly unconfirmed data are available on the criteria for the assessment of malignancy risk and patient outcome in endocrine tumors of the gastrointestinal tract. In these conditions the 2000 WHO classification with its standardized scheme of pathologic report constitutes a framework facilitating the assessment of tumor malignancy and has been regarded as useful for clinical purposes, providing the basis for proper management of the patients and for the design of treatment protocols. The classification is based on a combination of pathological and clinical features with parameters specific for each organ in which the endocrine tumors originate. Three main categories, one further subdivided into two subgroups, are considered: (1) well-differentiated endocrine tumors, further subdivided into tumors with benign and with uncertain behavior; (2) well-differentiated endocrine carcinomas, low grade; and (3) poorly differentiated endocrine carcinomas, high grade. In this review the differential tumor characteristics between the different categories are summarized. Moreover, the relevance of additional features with respect to tumor prognostication, chiefly the Ki-67 proliferation index and malignancy-associated genetic changes, is discussed with emphasis on the discrepancies emerging between tumors of foregut and of midgut origin.
authors.affiliation: Department of Pathology and Laboratory Medicine, Section of Anatomic Pathology, University of Parma, Parma, Italy. cesare.bordi@unipr.it
authors.forename: Cesare
authors.initials: C
authors.lastname: Bordi
authors.forename: Tiziana
authors.initials: T
authors.lastname: D'Adda
authors.forename: Cinzia
authors.initials: C
authors.lastname: Azzoni
authors.forename: Silvia
authors.initials: S
authors.lastname: Pizzi
authors.forename: Lorena
authors.initials: L
authors.lastname: Bottarelli
authors.forename: Francesca
authors.initials: F
authors.lastname: Mormandi
authors.forename: Tommaso
authors.initials: T
authors.lastname: Antonetti
authors.forename: Tu Vinh
authors.initials: TV
authors.lastname: Luong
authors.forename: Guido
authors.initials: G
authors.lastname: Rindi
mesh_terms: D014408:Biomarkers, Tumor / Q000032:analysis; D003937:Diagnosis, Differential; D004701:Endocrine Gland Neoplasms / Q000145:classification* / Q000175:diagnosis* / Q000473:pathology; D005770:Gastrointestinal Neoplasms / Q000145:classification* / Q000175:diagnosis* / Q000473:pathology; D006801:Humans; D019394:Ki-67 Antigen; D008940:Mitotic Index; D009361:Neoplasm Invasiveness / Q000175:diagnosis* / Q000235:genetics / Q000473:pathology; D011379:Prognosis; D014944:World Health Organization
chemical_list: D014408:Biomarkers, Tumor; D019394:Ki-67 Antigen