[Preoperative classification of malignant stomach tumors].

Based on the case report of a 51 year-old patient presenting with a lymphoepithelioma like gastric cancer, we discuss the diagnostic challenge to differentiate this entity from gastric non-Hodgkin lymphoma. Since high-level lymphoid stromal reactions are rarely associated with gastric adenocarcinoma, misinterpretation can occur easily. In addition to the lymphoepithelioma like gastric cancer that is often associated with a demonstrable EBV association of the tumor cells, synchronous development of gastric carcinoma and lymphoma must be considered. Establishment of a correct diagnosis requires multiple, deep and multifocally sampled gastric biopsies, and immunohistochemical and molecular techniques to supplement conventional histology. Only through this procedure are correct characterization and classification of these unusual gastric neoplasms possible.