What Does Aganglionosis Mean on a Pathology Report?

When you receive a pathology (biopsy) report for suspected Hirschsprung disease, the most important word you are likely looking for is aganglionosis. Simply put, “aganglionosis” means the total absence of nerve cells (called ganglia) in the wall of the large intestine. Normally, these nerve cells tell the bowel muscles to relax and move stool along. Without them, the bowel stays tightly squeezed shut, causing a severe blockage. Finding aganglionosis on a biopsy is how doctors officially confirm a diagnosis of Hirschsprung disease ^[1][2].

Receiving this diagnosis can be overwhelming, and reading a pathology report full of medical jargon often makes the experience even more confusing. Below is a guide to help you understand the types of biopsies and other common terms you might see on your child’s report.

Types of Biopsies

At the very top of the report, you might see a description of how the tissue was collected:

• Suction rectal biopsy (SRB): This is the most common first-line test. It is a quick bedside procedure that uses gentle suction to take a tiny snippet of the bowel lining without the need for general anesthesia or stitches ^[3].
• Full-thickness biopsy: Sometimes, a suction biopsy doesn’t capture enough tissue to be absolutely certain ^[4]. In those cases, a surgeon may need to take a deeper, full-thickness sample in the operating room to confirm the diagnosis ^[5].

Key Terms on the Report

Besides aganglionosis, pathologists look for other clues in the tissue sample to understand what is happening in the bowel. You may see these terms:

• Hypertrophic nerve trunks: Because the normal nerve cells are missing, the remaining nerve fibers in the bowel try to compensate by working harder. As a result, they grow thicker and larger than normal ^[6][7]. The presence of these thickened, enlarged nerve fibers strongly supports a diagnosis of Hirschsprung disease ^[8]. Sometimes, these enlarged nerves aren’t seen in the biopsy. This can suggest that the disease affects a longer section of the bowel (“long-segment” disease) rather than just the lowest part of the colon (“short-segment” disease) ^[6][9]. Please do not panic if this is the case—surgeons have effective, well-established techniques to treat both short- and long-segment Hirschsprung disease.
• Transition zone: This refers to the area of the bowel where the tissue changes from completely healthy (having normal nerve cells) to aganglionic (having no nerve cells) ^[10]. The surgical team needs to know exactly where the healthy bowel begins so they can remove the non-functioning section and connect the healthy bowel to the rectum ^[11]. If the initial biopsy doesn’t find the exact transition zone, surgeons will often do rapid biopsies called frozen sections during the surgery ^[10]. This allows a pathologist to check the tissue in real-time, ensuring only healthy bowel is left behind ^[12].
• Ganglion cells: These are the actual nerve cells that are missing in a child with Hirschsprung disease. If the report says “no ganglion cells identified,” it confirms aganglionosis ^[1].

Special Stains Used in the Lab

Nerve cells are incredibly small and can be difficult to see under a microscope using standard lab dyes. To be absolutely certain, pathologists use special chemical stains on the tissue:

• Calretinin: This is a highly accurate stain used to highlight normal nerve cells ^[13]. If the calretinin stain is described as “negative” or “absent,” it confirms that there are no normal nerve cells in that tissue sample ^[14].
• Acetylcholinesterase (AChE): This stain highlights the overgrown, thickened nerve fibers. If the report says AChE staining is “positive” or shows “hyperinnervation,” it is a classic sign of Hirschsprung disease ^[15][16].
• Hematoxylin-eosin (H&E): This is the traditional pink and purple stain used in pathology. While it gives a good general picture, special stains like calretinin and AChE are often needed because H&E alone has limitations when looking for tiny, absent nerve cells ^[14][17].
• Inflammation markers: Your report might also mention whether there are signs of inflammation. This is checked to rule out enterocolitis, a common but serious bowel infection that babies with Hirschsprung disease can develop, which may require immediate treatment ^[18].

Understanding these terms can help you feel more informed and prepared when you discuss the next steps, including surgical options, with your child’s care team.