Pathology . a benign encysted tumor of the skin, especially on the scalp, containing sebaceous matter; a sebaceous cyst.
British . a large, crowded city or a crowded urban district: London is the great wen of England.
That's the definition of 'wen'. My mother had a wen and I hated doing her hair because it was so awful to me. Now, there's a quite respected and I understand pretty good line of hair care products from Wen. I can't find out where the name came from, but I'm sure there is a good reason for it that has nothing to do with the wen I knew.
To me, it's as much a turnoff as restaurants called 'The Feed Lot', that I mentioned above, I think.