[Stromal tumors of the digestive tract. Prognostic evaluation of a series of 36 cases].

Clinical outcome of gut's stromal tumors is difficult to predict by morphological data. The prognostic significance of a set of morphological criterias and immunostaining for proliferating cell nuclear antigen (PCNA) was studied. Thirty six tumours were classified benign (group A) or malignant (group B) according to ten year follow-up. Patient's sex and age, site of origin, tumour size, mitotic count and cytonuclear atypia were considered. Growth kinetic was studied by immunohistochemical analysis of PCNA (PC 10, DakoR). In univariate analysis, mitotic count, PCNA index, tumor size and cytonuclear atypia were associated with patient outcome. However, in multivariate analysis, only mitotic count and tumour size were independent prognosis factors. Thus, mitotic count remains the best prognostic indicator for these tumours since a cut off value of 2 mitosis/high power field allows an accurate prognosis in 33/36 tumors.