Original ArticlesPHOX2B Immunostaining A Simple and Helpful Tool for the Recognition of Ganglionic Cells and Diagnosis of Hirschsprung DiseaseDrabent, Philippe MSc*,†; Bonnard, Arnaud MD, PhD‡,§; Guimiot, Fabien MD, PhD§,∥; Peuchmaur, Michel MD, PhD*,§; Berrebi, Dominique MD, PhD*,§Author Information Departments of *Pathology ‡Pediatric Surgery ∥Developmental Biology, Robert Debré Hospital, APHP †Sorbonne Université §Université de Paris, Paris, France Conflicts of Interest and Source of Funding: The authors have disclosed that they have no significant relationships with, or financial interest in, any commercial companies pertaining to this article. Correspondence: Dominique Berrebi, MD, PhD, Service D’anatomo-pathologie, Hôpital Robert Debré, 48 Boulevard Sérurier, Paris 75019, France (e-mail: [email protected]). The American Journal of Surgical Pathology: October 2020 - Volume 44 - Issue 10 - p 1389-1397 doi: 10.1097/PAS.0000000000001528 Buy Metrics Abstract Hirschsprung disease (HD) is a congenital disorder of the enteric nervous system that occurs in ∼1 in 5000 live births. It is characterized by the absence of ganglionic cells (GCs) in the distal intestine. The diagnosis relies on the thorough analysis of a rectal suction biopsy (RSB), which must show a complete absence of GCs after careful examination of at least 100 serial sections. Such a negative characteristic explains the difficulty of this diagnosis. Moreover, GCs may be immature in very young or preterm born children, making them hard to recognize. Therefore, ancillary techniques have been developed as diagnostic help, such as acetylcholinesterase histochemistry and calretinin immunostaining. These techniques reveal only indirect clues, focusing mainly on the changes in nerve fibers, but not on GCs themselves. As PHOX2B has been shown to be a very specific transcription factor in GCs and in progenitor enteric nerve cells, we have assessed (i) PHOX2B immunostaining in immature enteric ganglia and (ii) the use of PHOX2B immunostaining for the recognition of GCs on RSBs for suspicion of HD. We have observed PHOX2B expression in all GCs, both mature and immature, and its complete absence in Hirschsprung cases. We suggest that the use of PHOX2B immunostaining is of great help (i) in the recognition of GCs on RSBs regardless of their differentiation and therefore (ii) in the diagnosis of HD. Copyright © 2020 Wolters Kluwer Health, Inc. All rights reserved.