Most common ovarian tumour to undergo torsion:
**Core Concept**
The most common ovarian tumor to undergo torsion is often a dermoid cyst, also known as a mature teratoma. This type of tumor is typically benign and composed of multiple tissue types, including skin, hair, and teeth. The pedunculated nature of dermoid cysts makes them more susceptible to torsion.
**Why the Correct Answer is Right**
Dermoid cysts are prone to torsion due to their pedunculated attachment to the ovary. When the pedicle twists, it can compromise blood flow to the tumor, leading to ischemia and potentially life-threatening consequences. The twisting of the pedicle can occur due to various factors, such as ovarian enlargement, increased abdominal pressure, or other mechanical factors. The risk of torsion is higher in dermoid cysts compared to other types of ovarian tumors due to their characteristic pedunculated attachment.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because mucinous cystadenomas are not typically prone to torsion. While they can be large and pedunculated, their structure and attachment to the ovary make torsion less likely.
**Option B:** This option is incorrect because serous cystadenomas are generally not as susceptible to torsion as dermoid cysts. Their attachment to the ovary is often more solid, reducing the risk of twisting.
**Option C:** This option is incorrect because fibromas are typically solid tumors with a more robust attachment to the ovary, making torsion less likely.
**Clinical Pearl / High-Yield Fact**
It is essential for clinicians to recognize the risk factors for ovarian torsion, including the presence of a pedunculated tumor, and to act promptly in cases where torsion is suspected.
**Correct Answer:** D. Dermoid cyst.