Which are seen in endodermal sinus tumor:
**Core Concept**
Endodermal sinus tumor (EST), also known as yolk sac tumor, is a rare and malignant germ cell tumor that primarily affects the gonads. It is characterized by the presence of Schiller-Duval bodies, which are a distinctive histopathological feature of this tumor.
**Why the Correct Answer is Right**
The correct answer is related to the histopathological features of endodermal sinus tumor. Schiller-Duval bodies are a hallmark of EST and consist of a central blood vessel surrounded by embryonic cells, which are embedded in a fibrous stroma. The presence of these structures is diagnostic of EST and helps differentiate it from other types of germ cell tumors.
**Why Each Wrong Option is Incorrect**
* **Option A:** This option is incorrect because while alpha-fetoprotein (AFP) is a tumor marker associated with EST, it is not a histopathological feature of the tumor.
* **Option B:** This option is incorrect because while the tumor often affects the gonads, it can also occur in extragonadal sites, such as the sacrum, retroperitoneum, and mediastinum.
* **Option C:** This option is incorrect because while embryonic cells are present in EST, they are not a specific histopathological feature of the tumor.
**Clinical Pearl / High-Yield Fact**
Schiller-Duval bodies are a diagnostic hallmark of endodermal sinus tumor, and their presence in a tumor should raise suspicion for this diagnosis.
**Correct Answer:** D. Schiller-Duval bodies.