[The usefulness of immunohistochemical methods for the anatomopathologic diagnosis]

In order to determine the value of immunohistochemical staining methods for the morphologic diagnosis, we studied 949 histologic specimens sent for consultation to the Immunohistochemistry Laboratory of Department of Pathology of the Medical School of Botucatu in the period 1984-1989. All case were submitted to the immunoperoxidase staining with the methods PAP or ABC. Immunohistochemical stains confirmed the original morphologic diagnosis in 468 cases (49.3%); made the definitive diagnosis from a list of differential diagnostic possibilities in 244 cases (25.7%); provided contributory information in 74 cases (7.8%); were non-contributory in 114 cases (12%) and rendered an unsuspected diagnosis in 49 cases (5.2%). In some cases with non-contributory information the differences in methods of fixation might have led to suboptimal preservation of tissue antigens. The immunohistochemical staining may provide important and sometimes essential informations for definitive diagnosis. This technique was particularly useful for differential diagnosis between carcinoma, lymphoma and melanoma.