Polka dot sign on CT is a feature of
## **Core Concept**
The "polka dot sign" is a radiological finding seen on computed tomography (CT) scans. It is associated with a specific pathological condition affecting the liver. This sign is characterized by the appearance of multiple small dots within the liver parenchyma, resembling a polka dot pattern.
## **Why the Correct Answer is Right**
The correct answer, **B. Hepatic cavernous hemangioma**, is right because the "polka dot sign" is indeed a feature of hepatic cavernous hemangiomas. Hepatic cavernous hemangiomas are benign liver lesions composed of large, blood-filled spaces (caverns). On CT scans, particularly after contrast administration, these lesions can exhibit a characteristic appearance where small dots represent enhancing fibrofatty stroma within the lesion, giving it a "polka dot" appearance.
## **Why Each Wrong Option is Incorrect**
- **Option A:** This option is incorrect because while liver cysts do appear on CT scans, they typically do not exhibit the "polka dot sign." Liver cysts are usually simple, fluid-filled structures that appear as well-defined, hypodense lesions without internal enhancement or the characteristic dot pattern.
- **Option C:** This option is incorrect because metastatic liver disease can cause a variety of appearances on CT, including multiple hypodense lesions. However, the "polka dot sign" is not a typical descriptor for metastatic disease.
- **Option D:** This option is incorrect because while hepatocellular carcinoma (HCC) can have a variety of appearances on CT, including hyperdense or hypodense lesions with or without enhancement, it does not characteristically exhibit a "polka dot sign."
## **Clinical Pearl / High-Yield Fact**
A key clinical pearl is that the "polka dot sign" on CT is highly suggestive of **hepatic cavernous hemangioma**, particularly when seen in a lesion with other characteristic features such as peripheral enhancement and a well-defined border. This sign can help differentiate hemangiomas from other liver lesions.
## **Correct Answer: B. Hepatic cavernous hemangioma**