This has changed a lot, especially over the last couple of years, a lot due to the F# project.
You should look at self-hosted NancyFx or ServiceStack with F# as a good alternative to Node.js
The fact that the "other solutions" aren't popular is probably just because C# is the go to language in windows/.NET shops that already have knowledge and infrastructure. It's not that they are technically inferior.
Yes, other solutions exist, no those solutions aren't hugely popular in the grand scheme of things.