Ki-1-positive anaplastic large cell lymphoma: a morphologic and immunologic study of 14 cases

This report analysed the phenotype of fourteen cases of Ki-1-positive anaplastic large cell lymphoma, recently described high-grade malignant lymphoma. In 12 cases the neoplasm involved lymph nodes, two patients presented with primary extra-lymphoid involvement (stomach, larynx), whereas secondary involvement of the skin was observed in one patient. Immunohistochemical study revealed B-cell phenotype in seven cases; three cases presented T-cell specific markers; in three cases we found antigens characteristic for both lymphoid lineages and one case presented null phenotype. Ki-1 (CD30) antigen was found in every of 14 cases, and LeuM1 (CD15) antigen was not expressed in any of studied cases. In two cases we revealed the expression of cytokeratins (CAM 5,2). The foregoing results confirm heterogeneity of this neoplasm and suggest careful interpretation of the results of morphologic and immunohistochemical findings in any pleomorphic and anaplastic tumour.