Background: Due to their nonspecific symptoms, foreign bodies in the aerodigestive tract (FBA) are often misdiagnosed as respiratory conditions, especially when unwitnessed, posing significant risks for morbidity and mortality in the pediatric population. Case Presentation: We report a case of an otherwise healthy 4-month-old, predominantly breastfed infant with episodic "honking" breathing, choking with feeds, and a 2-month history of recurrent croup episodes requiring emergency services and an hospital admission. After referral to pediatric otolaryngology/respirology, a flexible laryngoscopy revealed a diagnosis of mild laryngomalacia, inconsistent with the severity of symptoms. A formal airway evaluation was performed, including supraglottoplasty.

Results: Unexpectedly, extraluminal pulsatile tracheal compression was found, with correlating computed tomography findings of an innominate artery variation and a paraesophageal abnormality. This abnormality appeared as a fluid-filled density between the esophagus and trachea on magnetic resonance imaging, without patency to the esophagus on Upper GI series. Differential diagnoses included vascular malformation, esophageal diverticulum, and bronchogenic/foregut duplication cyst. Although evaluation with echoendoscopy was considered, collaboration with general/thoracic surgery for a flexible esophagoscopy revealed a 2-cm breast pump membrane embedded in a pseudo-diverticulum with a sealed esophageal perforation, which concluded with successful object removal via forceps. The patient's respiratory symptoms have resolved; however, persistence of the pseudo-diverticulum on follow-up imaging and endoscopy warrants ongoing surveillance.

Conclusion: This case demonstrates the challenging diagnosis of a breast pump membrane as an unexpected esophageal FBA, compounded by nonspecific respiratory symptoms and the membrane's near-radiolucency on standard imaging. The exhibited multidisciplinary, collaborative approach was fundamental for the complication-free removal of the membrane.