Natural history, clinicopathologic classification and prognosis of gastricECL cell tumors

A series of 50 gastric endocrine tumors classified according to Rind et al. [1] comprised 12 small cell neuroendocrine carcinomas (NEC) and 38 ECL cel l carcinoids, of which 22 associated with type A chronic atrophic gastritis (A-CAG), eight with hypertrophic gastropathy due to combined Multiple Endo crine Neoplasia and Zollinger/Ellison syndrome (MEN/ZES), and eight sporadi c. Variables found to predict tumor malignancy were: size >2 cm, >2 mitoses and >130 Ki67 positive cells/ 10 high power fields (HPF), grade 2 or 3 his tology, angioinvasion, p53 protein nuclear accumulation, and the presence o f a single tumor. None of these factors increased significantly the predict ing ability of tumor classification itself, although grade 2+3 shows 100 pe rcent negative predictive value and Ki67 and angioinvasion 100 percent posi tive predictive value. When the mostly non-malignant A-GAG and MEN-ZES tumo rs were analysed against the mostly malignant sporadic acid NEC tumors, a p ositive predictive value of 90 percent and a negative predictive value of 9 3 percent was obtained. Investigation of a larger tumor series is under way with the aim to develop an optimal model for prognostic evaluation of gast ric endocrine tumors.