Paul Masson Rare Souzao Port 1852 (Unopened)

[Radark Krevial]

First of all pardon my ignorance, since I am not sure on whether this wine is valuable or not. I was given this wine as a gift and even though I can say that I am quite familiar in winery, I have never obtained a wine of this age. Is it an antique? and how valuable is it? And if it has no monetary value, what's the cause of it? Thanks!