Question

The most likely diagnosis in a newborn with a radio-opaque shadow and an air-fluid level in the chest, along with a hemivertebra of the 6th thoracic vertebra on a plain x-ray, is:

• A. Congenital diaphragmatic hernia
• B. Esophageal duplication cyst
• C. Bronchogenic cyst
• D. Staphylococcal pneumonia

Hint:

Air-fluid level plus a hemivertebra in a newborn's chest points to a foregut duplication (neurenteric) cyst, not a bronchogenic cyst.

Answer 1

The Correct Option is B

Step 1: Read the clues in the x-ray.
A newborn with a rounded, fluid-filled shadow in the chest that also shows an air-fluid level points to a cystic structure that connects with the gut lumen, since air only gets inside a cyst if it opens into the bowel or esophagus.

Step 2: Link the finding to the spine.
The x-ray also shows a hemivertebra at the sixth thoracic level. A vertebral segmentation defect sitting next to a chest cyst is the hallmark of a cyst that formed from the same part of the embryo as the spine, not from the lung buds.

Step 3: Trace the embryology.
In early development, the notochord and the gut share one origin. If the two fail to split apart the way they should, a tract of tissue is left behind that can form a cyst attached to both the gut wall and the vertebral column. This defect is called split notochord syndrome, and the cyst it produces is a foregut duplication cyst of the esophageal or neurenteric type. Because part of this cyst opens into the esophagus, it fills with air and fluid, giving the air-fluid level, and the linked spinal defect gives the hemivertebra.

Step 4: Rule out the other options.
A congenital diaphragmatic hernia shows bowel loops with several air-fluid levels in the chest, but it does not cause a vertebral defect. A bronchogenic cyst comes from the breathing-tube side of the foregut, sits away from the spine, and does not normally connect to the airway or gut, so it does not carry air and is not linked to a hemivertebra. Some older answer keys list bronchogenic cyst here, but a bronchogenic cyst has no connection to the gut lumen and no tie to vertebral anomalies, so it does not fit this presentation as well as a foregut duplication cyst does. Staphylococcal pneumonia gives patchy consolidation and pneumatoceles, not a single cystic shadow tied to a vertebral defect.

Final Answer:
The combination of an air-fluid level in the chest with a hemivertebra is the classic picture of a foregut (esophageal) duplication cyst of the neurenteric type.
\[ \boxed{\text{Esophageal duplication cyst}} \]