Primary gastric CD30 (Ki-1)-positive large cell non-Hodgkin's lymphomas: a clinicopathologic analysis of six cases

Background. The CD30/Ki-1 antigen characterizes a series of non-Hodgkin's lymphomas (NHL) predominantly showing anaplastic large cell (ALCL) morphology and frequently involving the skin and other extranodal sites. In cutaneous large cell lymphomas, the CD30 expression was indicated as a favorable prognostic marker independently from cytology, anaplastic versus nonanaplastic. The stomach is the most common site of extranodal lymphomas in the adult population, but primary gastric CD30+ lymphomas have been reported rarely. Methods. The clinical, morphologic, and immunohistochemical features of six cases with primary CD30/Ki-1+ gastric large cell lymphomas were analyzed. Results. The mean age of patients was 64 years with a prevalence of women (M:F ration = 1:2). Patients were assigned to Stage IE or IIE. Three of them died of disease, whereas the others are still alive (mean follow-up, 18 months). Three of six cases had ALCL morphology, whereas other cases had centroblastic, immunoblastic, and high-grade mucosa-associated lymphoid tissue lymphoma. Immunohistochemistry revealed a B-cell phenotype in three of six cases; a T-cell phenotype in one of six cases; and a null, non-B, non-T phenotype in two of six cases. Conclusions. Within CD30+ primary gastric large cell lymphomas, cytology, anaplastic versus nonanaplastic, did not affect clinical presentation and/or prognosis. The survival rate of the patients studied is in keeping with literature reports regarding prognosis of primary high-grade gastric NHL. The findings suggest that clinical behavior of this extranodal lymphoma is more closely related to clinical symptoms and initial stage of disease than to CD30 expression.