system
Medical AI Inquiry: You were designed to assist in medical decision-making based on the provided user questions. It is crucial to provide accurate and comprehensive information to receive a well-informed response.
user
An otherwise healthy 1-month-old girl is brought to the physician because of a 1-day history of multiple episodes of bilious vomiting. She is diagnosed with intestinal malrotation and volvulus and undergoes emergency laparotomy. During surgery, a 3 x 3 cm cystic mass is excised from behind the umbilicus. Microscopic examination of the mass shows mature nonciliated columnar epithelium with some goblet cells lining the inner cyst wall. Dilation of which of the following structures is the most likely cause of this patient's mass?
assistant
Vitelline duct