Calretinin and microtubule-associated protein-2 (MAP-2) immunohistochemistry in the diagnosis of Hirschsprung's disease.

Background/purpose: Identifying ganglion cells by rectal suction biopsy is a basic diagnostic tool for the diagnosis of Hirschsprung's disease (HD). However, the difficult interpretation of conventionally processed slides often necessitates ancillary staining methods. The aim of this study was to evaluate the usefulness of calretinin and microtubule-associated protein-2 (MAP-2) immunohistochemistry in the diagnosis of HD.

Methods: We analyzed 52 rectal suction biopsy specimens (37 from 15 HD patients and 15 from 7 non-HD patients) for ganglion cells with calretinin and MAP-2 immunohistochemistry. We also analyzed full-thickness, frozen biopsy samples obtained from 15 HD patients who underwent surgery utilizing calretinin and MAP-2 immunohistochemistry.

Results: Both calretinin and MAP-2 positively stained ganglion cells in the submucosal plexus of the ganglionic bowel but not aganglionic bowel. Calretinin usually stained ganglion cell cytoplasm and nuclei more intensely than MAP-2, which only stained cytoplasm. No nerve fiber staining in the submucosal layer was observed for either antibody. In 21.1% (11/52) of samples, calretinin and MAP-2 staining found ganglion cells which were reported not to have ganglion cells in the original surgical pathology reports. Immunohistochemical staining for calretinin using paraffin-embedded tissue sections after cryostat sections clearly demonstrated decreased staining intensity compared to MAP-2.

Conclusion: Calretinin and MAP-2 are useful diagnostic markers for diagnosing HD in rectal suction biopsies. These complementary methods could ameliorate the diagnostic difficulties associated with HD.