**Core Concept**
FIGO staging is a widely accepted system for classifying the extent of spread in endometrial cancer. It takes into account the depth of myometrial invasion and the presence of lymph node metastasis. The paraaortic lymph nodes are a common site for metastasis in endometrial cancer.

**Why the Correct Answer is Right**
The correct staging of endometrial cancer with paraaortic lymph node metastasis involves assessing the depth of myometrial invasion and the involvement of lymph nodes. In FIGO staging, the presence of paraaortic lymph node metastasis indicates Stage IIIc disease. This is because the paraaortic lymph nodes are a group of lymph nodes located in the abdominal cavity that can be involved in the spread of endometrial cancer. The involvement of these lymph nodes is a critical factor in determining the stage of the disease.

**Why Each Wrong Option is Incorrect**
* **Option A:** Incorrect because it does not account for the presence of paraaortic lymph node metastasis, which is a critical factor in determining the stage of the disease.
* **Option B:** Incorrect because it does not take into account the depth of myometrial invasion, which is an important factor in FIGO staging.
* **Option C:** Incorrect because it does not accurately reflect the involvement of paraaortic lymph nodes in the staging of endometrial cancer.

**Clinical Pearl / High-Yield Fact**
It's essential to remember that FIGO staging is a critical factor in determining the prognosis and treatment of endometrial cancer. The presence of paraaortic lymph node metastasis is a significant factor in staging, and it can have a substantial impact on treatment decisions.

**Correct Answer: C. Stage IIIc**