Final answer:
Cervical carcinoma is the most common primary tumor leading to metastatic vulvar cancer. Cancers have specific tendencies to metastasize to particular organs, so early detection and treatment are critical for better outcomes.
Step-by-step explanation:
The most common primary tumor causing metastatic vulvar cancer is cervical carcinoma. Cervical cancer has the capacity to spread through local extension to adjacent tissues or organs such as the vulva. The cells from a cervical carcinoma can metastasize and lead to secondary tumors in the vulva, which is why it's crucial to diagnose and treat cervical cancer early. It's worth noting that while cervical cancer can metastasize to the vulva, the most common types of primary vulvar cancers are vulvar squamous cell carcinoma and vulvar melanoma. However, these typically originate within the vulva itself. The tendency for different types of cancers to metastasize to particular organs, such as the brain, lungs, bones, and liver, once again highlights the pathophysiology associated with metastatic cancers.