Cork screw appearance on barium swallow is seen in:
**Core Concept**
The "cork screw" appearance on a barium swallow is a radiographic finding associated with a specific esophageal pathology. This appearance is due to the presence of a mass or a stricture that causes the esophagus to twist and turn in a helical fashion, resembling a cork screw.
**Why the Correct Answer is Right**
The correct answer is associated with achalasia, a motility disorder of the esophagus characterized by the failure of the lower esophageal sphincter (LES) to relax. This leads to a functional obstruction, causing the esophagus to dilate and twist, resulting in the characteristic "cork screw" appearance on a barium swallow. The twisting motion is due to the hypertensive LES and the failure of peristalsis in the distal esophagus.
**Why Each Wrong Option is Incorrect**
* **Option A:** This is incorrect because esophageal cancer typically causes a stricture or a mass that may cause an irregular outline on a barium swallow, but not a cork screw appearance.
* **Option B:** This is incorrect because GERD (Gastroesophageal Reflux Disease) is associated with a hiatal hernia and reflux esophagitis, which may cause a dilated esophagus but not a cork screw appearance.
* **Option C:** This is incorrect because Zenker's diverticulum is a mucosal outpouching in the upper esophagus, which may cause a filling defect or an outpouching on a barium swallow, but not a cork screw appearance.
**Clinical Pearl / High-Yield Fact**
Achalasia is often associated with a "bird's beak" appearance on a barium swallow, which is the tapering of the distal esophagus due to the functional obstruction caused by the hypertensive LES.
**Correct Answer:** A. Achalasia