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 d ue to the exceeding rarity of these tumours; many of the reported cases wer e felt to be similar to node-based lymphomas, We describe two cases of prim ary gastric T-cell lymphoma with evidence of origination from intraepitheli al T-lymphocytes. Methods and results: Both tumours were restricted to the stomach; one displ aying a large ulcerated mass, the other a widespread superficial tumour man ifestation. Histologically the first tumour was composed of sheets of mediu m-sized lymphoid cells showing marked epitheliotropism at the edge of the u lcer, and a CD3+, CD4-, CD8-, CD20-, CD56-, CD103+, beta F1+ phenotype. The second case differed histologically and immunophenotypically from the firs t case, In addition to lamina propria and submucosal infiltration, the lymp homa contained an extensive intraepithelial component even in large areas w ithout other evidence of tumour. The neoplastic. cells ranged in size from small to medium and large. Immunohistology disclosed a CD3+, CD4+, CD8-, CD 20-, CD56-, beta F1+ phenotype, Staining for CD103 could not be performed i n this case since frozen material was not available. Conclusions: The prominent epitheliotropism, the marked intraepithelial gro wth and the expression of CD103 strongly imply a derivation of these primar y gastric lymphomas from intraepithelial T-lymphocytes, Additional studies of larger series will clarify whether the findings described here are typic al of primary gastric T-cell lymphomas.