Unravelling a pediatric enigma: coexisting retroesophageal right subclavian artery and congenital colonic stenosis masquerading as cow's milk protein allergy and ileus in a neonate

Abstract

Background: Double alimentary tract obstruction due to congenital anomalies is a rare clinical occurrence, with limited cases published in medical literature. This article presents a unique case of coexisting retroesophageal right subclavian artery (RRSA) and congenital colonic stenosis (CCS), conditions that have not been previously documented together in pediatric population.

Case presentation: A Thai male newborn was born by cesarean section at gestational age of 41 weeks. One week before birth, intrauterine asphyxia and idiopathic bilateral intracerebral hemorrhage were diagnosed by prenatal ultrasonography. Despite postnatal interventions including a ventriculoperitoneal shunt and subsequent external ventricular drain, the intracerebral hemorrhage recurred and progressed. Concurrently, the patient experienced multiple episodes of post-feeding vomiting, intermittent abdominal distension, and regular defecation without constipation. Sepsis secondary to an infected shunt occurred, accompanied by marked abdominal distension. The physician clinically suspected non-IgE-mediated cow's milk protein allergy and ileus associated with sepsis. Tragically, the patient succumbed at seven months due to a brain abscess stemming from an infected external ventricular drain. Ultimately, postmortem examination unraveled double alimentary tract obstruction, consisting of RRSA and CCS. The RRSA, originating from proximal thoracic aorta, caused notable esophageal compression and functional stenosis which led to the frequent vomiting and reflux. The CCS involved the distal transverse colon, descending colon and proximal sigmoid colon, accounting for nearly 50% of the colon. The CCS was therefore the exact cause of intermittent abdominal distension. The stenotic colon contained submucosal and myenteric plexuses, excluding Hirschsprung disease.

Conclusion: This case highlights the diagnostic complexities of RRSA and CCS resulting in double gut obstruction and masquerading as non-IgE-mediated cow's milk protein allergy and sepsis-induced ileus. Awareness of these rare coexisting congenital anomalies can aid in early recognition, prevent misdiagnosis, enable timely management and improve outcomes for affected pediatric patients.

Keywords: Abdominal distension; Congenital colonic stenosis; Cow's milk protein allergy; Gut obstruction; Ileus; Misdiagnosis; Neonatal vomiting; Reflux; Retroesophageal right subclavian artery; Sepsis.

Fig. 1

(A) Abdominal X-ray at 2 months of age, taken during an episode of sepsis, showing multiple dilated bowel loops without air-fluid levels or pneumoperitoneum, consistent with marked abdominal distension. The VP shunt was visible. (B, C) Brain CT at 6 months of age revealing extensive bilateral encephalomalacia, hydrocephalus, and a hyperdense lesion (2.4 × 1.7 cm) in the right high frontal lobe, indicative of recent hemorrhage

Fig. 2

(A) Anterior view of the mediastinum and neck unveiled the retroesophageal right subclavian artery (a), right common carotid artery (b), left common carotid artery (c), left subclavian artery (d) and the right non-recurrent inferior laryngeal nerve (red arrow) of the vagus nerve (CN X). Arteries (b) to (d) directly originated from the aortic arch (e). No brachiocephalic trunk was observed. (B) Posterior view of the same specimen showing the retroesophageal right subclavian artery (a) arising from the proximal thoracic aorta (f) and coursing obliquely behind the esophagus (g). (C) Right posterolateral view of the same specimen illustrating notable esophageal impression (red arrowheads) caused by the retroesophageal right subclavian artery (a), which was reflected to the left

Fig. 3

(A) Reflection of the small intestine revealing the in situ colonic stenosis (red arrows) affecting the distal transverse colon (TC), descending colon (DC) and proximal sigmoid colon (SC) without fibrous adhesion between abdominal viscera. (B) The resected distal ileum to the rectum was repositioned into the abdominal cavity to illustrate the extent of colonic stenosis (red arrows) and a dilatated segment (yellow asterisk) of the transverse colon proximal to the stenosis. (C) The stenotic colon, comprising nearly 50% of the total colonic length, was significantly narrower than the ascending colon (AC) and rectum. (D) Comparative cross sections of the ascending colon, dilated proximal transverse colon, stenotic descending colon, and rectum. Mucosal folding was absent in the dilated transverse colon (yellow asterisk). The descending colon measured 0.6 cm in diameter at the narrowest stenotic segment (red arrow), making it 40–60% narrower than the unaffected colonic segment

Fig. 4

(A) Photomicrograph of the stenotic descending colon showing complete wall layers, including the mucosa (M), submucosa (S), muscularis propria (MP), and adventitia (Ad), along with the myenteric plexuses (yellow arrows). Submucosal fibrosis (blue asterisk) was observed in the stenotic region. H&E, 40× magnification. (B) A normal distribution of the ganglion cells (green arrows) in the myenteric plexuses was observed between the inner circular (IC) and outer longitudinal (OL) layers of the stenotic descending colon. H&E, 200x magnification