[Initial immunolabelling in the diagnosis of solid tumors undergoing cytologic studies (cytopuncture and imprints)]

A minimum immunocytolabelling panel was applied to cytologic specimens from 112 solid tumors obtained by operative specimen imprints or fine needle biopsies of superficial or deep organs. A confirmatory histopathologic study was performed subsequently in all cases. Cases were divided into two groups: group 1 (n = 69) included the malignant tumors exhibiting diagnostic morphologic features; this group served as a control. Group 2 (n = 43) included the undifferentiated malignant tumors that were not classifiable on the basis of routine cytomorphologic data. Immunocytolabelling was done using immunofluorescence and/or PAP and a minimum panel of monoclonal antibodies against keratin (KL1), epithelial membrane (EMA), vimentin, and leukocyte common antigens. In the overwhelming majority of cases, immunocytolabelling provided useful diagnostic information (carcinomas/malignant lymphomas, carcinomas/malignant melanomas, carcinomas/sarcomas, etc...). Some tumors simultaneously expressed an epithelial antigen and a vimentin-like antigen. The problem of such coexpression is discussed. In our opinion, immunocytolabelling of cytologic samples is especially useful for studying needle biopsy specimens of organs, particularly deep organs.