RESUMEN
The diagnostic distinction of some vascular tumors and Kaposi's sarcoma [KS] can be sometime difficult. Recently, a monoclonal antibody to human herpes virus- 8 latent nuclear antigen-1 has been demonstrated in Kaposi's sarcoma. In this study the usefulness of this antibody is evaluated to differentiate Kaposi's sarcoma from the other vascular lesions. Formalin-fixed, paraffin-embedded tissue sections [4 micro m] from 20 cases of Kaposi sarcoma, ten cases of capillary hemangioma [pyogenic granuloma], five cases of angiosarcoma, three cases of hemangioendothelioma, three cases of vascular transformation of lymph nodes were examined immunohistochemically for HHV-8 using mouse monoclonal antibody [NCL-HHV8-LNA], Novocastra, United Kingdom. It is specific for human herpesvirus type 8 latent nuclear antigen-1 [LNA-1]. Nuclear staining in tumor cells was considered a positive result. HHV-8 stain showed strong, diffuse, nuclear staining for human herpes virus 8 latent nuclear antigen-1 in all, 20/20 cases of Kaposi sarcoma [100%], whereas all cases of hemangioma, angiosarcoma, hemangioendothelioma and vascular transformation of lymph nodes were negative for this antigen. Immunohistochemistry for HHV-8 is a characteristic immunohistochemical marker of Kaposi sarcoma and considered as a very useful tool for differentiation between Kaposi sarcoma and other vascular lesions