Focal malignant lymphoma in gastric pseudolymphoma. Histologic and immunohistochemical study of a case

The authors report a case of a focal malignant lymphoma (ML)plasmacytic typesupervening in a gastric pseudolymphoma (PSL)diagnosed 6 years before and closely followed up. The diagnosis was made on endoscopic biopsy findings and confirmed by subtotal gastric resection. Immunohistochemical studies were performed both on surgical material andretrospectivelyon the initial series of biopsy specimens. The majority of the lymphoid cells of the PSL expressed the same immunoglobulin heavy and light chains as the cells of the MLwhich were characterized by the presence of monoclonal mu and kappa chains. These results suggest a close relationship between the PSL and the MLand support the hypothesis of the prelymphomatous nature of the gastric pseudolymphoma. The possible existence of focal malignant lesions among PSL suggests reevaluation of the role of surgical resection in its management. Endoscopic examination allows its diagnosis on biopsy materialbut it remains difficult to detect focal ML among the benign‐appearing lesion. For this reasonsurgical resection must be always performedregardless of the circumstances of the initial diagnosisboth as a means of final diagnosis and as therapy.