Stromal tumors of the jejunum and ileum.

Gastrointestinal stromal tumors (GISTs), as currently defined, are mesenchymal tumors of the gastrointestinal tract composed of spindled and/or epithelioid stromal cells that are neither mature Schwann cells nor smooth muscle cells. Many studies have lumped GISTs from all gut sites, when in fact these tumors differ histologically by location. In this study, we evaluated a set of parameters by both univariate and multivariate analysis to determine which parameters correlated with metastases in 36 GISTs from the jejunum and ileum, exclusively. The parameters included organoid architecture, cellularity, mitotic counts, epithelioid cell shape, mucosal invasion, tumor size, skeinoid fibers, nuclear pleomorphism, ischemic necrosis, immunohistochemical differentiation, and proliferating cell nuclear antigen labeling. We evaluated these retrospectively without knowledge as to the metastatic outcome of the tumors. By univariate analysis, dense cellularity, mitotic counts, epithelioid cell shape, mucosal invasion, and size were statistically significant correlates with metastases. By multivariate analysis, only dense cellularity and mitotic counts were independent correlates with metastases. Whether these features are useful predictors of behavior remains to be tested.