Usefulness of K-1 (CD-30) marker in Hodgkin's disease.

OBJECTIVE To identify Hodgkin's and Reed Sternberg like cells by a single Immunomarker (Ki-1; CD-30) and to highlight diagnostic specificity of these cells in Hodgkin's disease, as these cells are frequently encountered in other lymphoproliferative disorders on H&E sections. METHODOLOGY Seventy-nine histologically diagnosed cases of lymph node biopsies (59 cases of Hodgkin's disease, 15 cases of Non Hodgkin's lymphoma and 5 cases of non neoplastic lymphoid tissue) were subjected to Ki-1 (CD-30) immunostaining as all cases revealed Hodgkin's and/or Reed Sternberg like cells on H&E stained sections. RESULTS Out of 59 cases of Hodgkin's disease, 49 (83%) showed Ki-1 (CD-30) immunoreactivity for Reed Sternberg and Hodgkin's cells. None of the 15 cases of non-Hodgkin's lymphoma (2 small lymphocyte type, 11 diffuse large cells type, 2 lymphoblastic type) showed positive Ki-1 (CD-30) immunostaining. Only one case of the remaining 5 cases of non-neoplastic lymphoid lesion (2 toxoplasmic lymphadenitis, one histiocytic necrotizing lymphadenitis, one reactive hyperplasia and one chronic non specific lymphadenitis) showed positive Ki-1 immunostaining. CONCLUSION Ki-1 (CD-30) is a reliable marker for Hodgkin's Reed Sternberg like cells in histologically proven cases of Hodgkin's disease but not for similar cells encountered in other lymhoproliferative lesions.