Features of dysgerminoma are:
**Core Concept**
Dysgerminoma is a type of germ cell tumor that primarily occurs in the ovary. It is the most common type of malignant germ cell tumor in the ovary and is often associated with a favorable prognosis. Dysgerminomas are thought to arise from the primordial germ cells of the ovary.
**Why the Correct Answer is Right**
Dysgerminomas typically exhibit features such as a high mitotic rate, a uniform population of large, rounded cells with clear cytoplasm, and a well-defined border with the surrounding ovarian stroma. They are also often associated with the presence of large cells with prominent nucleoli, which are indicative of active cell division. Immunohistochemically, dysgerminomas are positive for OCT4, a marker of embryonic stem cells, and are also positive for CD117, also known as c-KIT.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because dysgerminomas are not typically associated with mucin production, which is more characteristic of serous and mucinous epithelial ovarian tumors.
**Option B:** This option is incorrect because while dysgerminomas can exhibit calcification, it is not a distinguishing feature of this tumor type.
**Option C:** This option is incorrect because dysgerminomas do not typically exhibit a biphasic pattern of differentiation, which is more characteristic of embryonal carcinoma.
**Clinical Pearl / High-Yield Fact**
Dysgerminomas are often associated with a favorable prognosis due to their high sensitivity to chemotherapy and radiation therapy. They are typically treated with surgical resection, followed by adjuvant therapy if necessary.
**Correct Answer: A. Features of dysgerminoma include a high mitotic rate, a uniform population of large, rounded cells with clear cytoplasm, and a well-defined border with the surrounding ovarian stroma.**