Cascarino, who scored 19 goals in 88 appearances for his country, will go under the knife after the World Cup and will take a step back from his punditry roles while he recovers.
"I was sent for an MRI scan and waited for the results. From the start, I was told it was probably an acoustic neuroma, the same as Debbie (His partner's sister), a benign tumour that can be very small and grow very slowly," said Cascarino, when writing in his column in the Times.
"You can have them for years without knowing it. Mine is about the size of a golf ball, which is alarming when you think about it, but the benign bit was a huge weight off my shoulders and in that respect, I'm very lucky.
"Why am I writing about this? Logistics, firstly. After the World Cup, I'll be having surgery and my rehabilitation could last for a couple of months, so I'll be disappearing for a while.
"The second reason is far more important. My roles with The Times and talkSPORT give me a platform to say please, don't be like me. In similar circumstances, get yourself checked. I understand now that I left it too long and the longer you leave anything, the bigger the risk."
When contacted Cas was his usual inimitable self: "I will ve back in the game soon:"