Apple core appearance on barium enema is seen in?
**Core Concept**
The "apple core" appearance on a barium enema is a radiological sign associated with a stricture or obstruction in the colon. This sign is characterized by a narrow, constricted segment of the colon with a normal caliber proximal and distal to the obstruction, resembling the core of an apple.
**Why the Correct Answer is Right**
The "apple core" appearance is typically seen in cases of colorectal cancer or other malignancies causing a stricture or obstruction in the colon. The narrowing of the colon lumen is due to the extrinsic compression by the tumor or the intrinsic growth of the tumor cells within the mucosa. The normal caliber of the colon proximal and distal to the obstruction is maintained due to the compensatory dilatation of the colon above and below the stricture.
**Why Each Wrong Option is Incorrect**
* **Option A:** This option is incorrect because the "apple core" appearance is not typically seen in cases of inflammatory bowel disease (IBD), such as Crohn's disease or ulcerative colitis, which may cause narrowing and strictures in the colon, but the appearance is usually more irregular and not as characteristic as in malignancies.
* **Option B:** This option is incorrect because the "apple core" appearance is not a feature of diverticulitis, which may cause narrowing and obstruction in the colon, but the appearance is usually more heterogeneous and not as characteristic as in malignancies.
* **Option C:** This option is incorrect because the "apple core" appearance is not a feature of ischemic colitis, which may cause narrowing and obstruction in the colon, but the appearance is usually more heterogeneous and not as characteristic as in malignancies.
**Clinical Pearl / High-Yield Fact**
The "apple core" appearance on a barium enema is a classic radiological sign of colorectal cancer, but it can also be seen in other malignancies causing a stricture or obstruction in the colon. It is essential to remember that this sign is not pathognomonic and must be correlated with clinical and endoscopic findings to establish a definitive diagnosis.
**Correct Answer:** D.