DIAGNOSTIC UTILITY OF CALRETININ IN SUSPECTED CASES OF HIRSCHSPRUNG’S DISEASE FROM COLORECTAL BIOPSIES TAKEN FROM CHILDREN AT THE KENYATTA NATIONAL HOSPITAL IN NAIROBI, KENYA- A RETROSPECTIVE CASE SERIES STUDY

Abstract

Background: Hirschsprung’s disease (HSD) is a pediatric colonic disorder marked by the absence of ganglion cells in the mucosa and myenteric plexi, causing functional intestinal obstruction. Diagnosis relies on rectal biopsy with Hematoxylin and Eosin (H&E), but subjectivity in ganglion cell recognition limits accuracy. Ancillary stains such as acetylcholinesterase have drawbacks, making Calretinin, which is a calcium-binding protein with immunoreactivity in ganglion cells and nerve fibers, the preferred marker. Its absence in the submucosa and myenteric plexus confirms HSD.
Objective: To determine the diagnostic utility of Calretinin in suspected HSD cases from colorectal biopsies at Kenyatta National Hospital.
Methodology: Paraffin blocks archived between January 2018 and December 2022 were retrieved. Slides were stained with H&E for initial diagnosis, then subjected to Calretinin immunohistochemistry (IHC) to assess ganglia and nerve fiber expression. Results were then analyzed using SPSS.
Results: Forty-eight cases were studied; median age was 1 year (range: 3 days-9 years), with males comprising 56.3%. Five biopsies (10.4%) were inadequate. Of 43 evaluable cases, 23 showed ganglion cells, and 20 were negative on H&E. Calretinin stained ganglion cells in 22 cases and was absent in 21, including one missed by H&E. Hypertrophied nerve fibers were consistently present in ganglion-negative cases. Agreement between H&E and Calretinin was excellent (κ = 0.953, p<0.001).
Conclusion: Calretinin IHC demonstrates high sensitivity, specificity, and diagnostic accuracy, with excellent agreement to H&E, supporting its role in confirming HSD.