[Hirschsprung's disease: the immunohistochemistry as ancillary method for the diagnosis.]

Background: the confirmatory diagnosis of Hirschsprung's disease is made by histopathological study. However, this procedure is limited with only hematoxylin and eosin staining, especially in biopsies of premature babies or when non-expert pathologists make the evaluation. The immunohistochemistry from ganglia cell calretinin has been used to reduce the risk of misdiagnosis. Our objective was to show the benefits of this antibody in diagnosis of Hirschsprung's disease in biopsy specimens. Methods: we evaluated patients with histopathological diagnosis of Hirschsprung's disease made by hematoxylin and eosin staining. We determined if there was enough paraffin block for immunohistochemistry with two markers: calretinin and neurofilaments. Three controls of autopsy of children under 3 years of age with other diagnosis were included. Results: of a total of 48 cases with histopathological diagnosis of Hirschsprung's disease only 13 had adequate tissue for immunohistochemistry. The immunohistochemistry confirmed the diagnosis in nine cases. In the other four cases there were initial misdiagnosis due to evidence of calretinin (ganglion cells) and, thus, Hirschsprung's disease was discarded. Conclusions: the use of immunohistochemistry allows confirming the diagnosis of Hirschsprung's disease and reduce the risk of a false-positive result with only hematoxylin and eosin staining.