Hirschsprung disease is the most common cause of neonatal colonic obstruction. It accounts for ~15-20% of all intestinal obstructions in the neonate. It can present later in life, as in this perceived case.
The main differential is a functional megarectum.
In this case it only came to light due to the dutiful examination of a maxillofacial surgeon, just prior to performing a mandibular resection for an ameloblastoma.
Retrospective questioning indicated the patient has not emptied her bowel for 3 months!
The patient/patient guardian declined rectal biopsy to confirm the strong suspicion of late presentation Hirschsprung's disease.