Immunohistochemical diagnostics of Hirschprungs disease using calretinin.

Histochemical diagnosis of Hirschsprung´s disease at our institution was introduced in the 1970s, calretinin imunohistochemistry on formalin fixed tissue was newly added in 2015. Employing both methods we were able to confirm Hirschsprung´s disease in 13 patients and exclude it in 34 patients since then. Calretinin seems highly reliable and easy to evaluate, it is not influenced by patient´s age, associated genetic features or the length of agangliosis. The number of inadequate samples was very low (3.8%). Histochemistry is useful as an adjunct tool to correct equivocal findings of calretinin staining and to facilitate diagnosis of short and ultra-short Hirschsprung´s disease. Serial biopsies from distal rectum and adjacent large bowel were obtained to assess the length of agangliosis preoperatively. The results of calretinin imunohistochemistry correlated very well with the findings in the colectomy specimens. In contrast, the length of affected bowel detected by histochemistry was often underestimated because acetylcholinesterase activity always diminishes orally irrespective of the length of aganglionic portion.