Origin of primary gastric T-cell lymphomas from intraepithelial T-lymphocytes:: report of two cases

Aims: The classification of primary gastric T-cell lymphomas is uncertain due to the exceeding rarity of these tumours; many of the reported cases were felt to be similar to node-based lymphomas, We describe two cases of primary gastric T-cell lymphoma with evidence of origination from intraepithelial T-lymphocytes. Methods and results: Both tumours were restricted to the stomach; one displaying a large ulcerated mass, the other a widespread superficial tumour manifestation. Histologically the first tumour was composed of sheets of medium-sized lymphoid cells showing marked epitheliotropism at the edge of the ulcer, and a CD3+, CD4-, CD8-, CD20-, CD56-, CD103+, beta F1+ phenotype. The second case differed histologically and immunophenotypically from the first case, In addition to lamina propria and submucosal infiltration, the lymphoma contained an extensive intraepithelial component even in large areas without other evidence of tumour. The neoplastic. cells ranged in size from small to medium and large. Immunohistology disclosed a CD3+, CD4+, CD8-, CD20-, CD56-, beta F1+ phenotype, Staining for CD103 could not be performed in this case since frozen material was not available. Conclusions: The prominent epitheliotropism, the marked intraepithelial growth and the expression of CD103 strongly imply a derivation of these primary gastric lymphomas from intraepithelial T-lymphocytes, Additional studies of larger series will clarify whether the findings described here are typical of primary gastric T-cell lymphomas.