I had a ganglion on my wrist for ages then (for the first time in 20 years and hadn't had a drink) I tripped over the caravan steps and broke my wrist (first breakage ever too!!!). Anyway, when the plaster cast was taken off, the ganglion had disappeared, never to return!!!! There you go, another solution to a ganglion.
I've never see a ganglion that far up the arm, and it's usually full of something that Mobil and Shell would be proud to call grease and with a viscosity of 190W......blood would not come gushing out.