Immunohistochemistry as an aid in the diagnosis of Hirschsprung's disease

The interpretation of rectal suction mucosal biopsies taken for the purpose of ruling out Hirschsprung's disease (HD) can be especially difficult in neonatal patients because of ganglion cell (GC) immaturity. Acetylcholinesterase histochemistry on frozen sections can be helpful but requires experience and may be complicated by excessive mucosal hemorrhage. The authors retrospectively have studied 27 patients, including 11 patients with HD, on whom conventionally fixed and embedded tissue was available, using an immunoperoxidase system directed against neuron-specific enolase (NSE) and S100 protein. NSE immunostaining produced intense staining of GC perikarya, greatly facilitating recognition of small immature forms. S100 immunostaining also highlighted GC as prominent negative stained cells surrounded by the positivity of Schwann cells. Both stains were helpful in demonstrating the overall pattern of microinnervation and its relationship to possible GC. The authors conclude that NSE and S100 immunostaining may facilitate interpretation of rectal mucosal biopsies when Hirschsprung's disease is being considered as a possibility.