The 60-year-old, who played for North End between 1975 and 1979 before going on to play for Manchester City, Brighton, Liverpool and the Republic of Ireland, made the revelation on his radio show in Spain where he has been working as a sports broadcaster since retiring from football in 1989.
Robinson told listeners he had discovered a lump under his arm at the end of October, which doctors say is advanced melanoma
He said on the programme: “I would prefer not to have to fight this battle, but regrettably I’m in that battle and I’m determined I’m going to beat it.
“On October 30 I had a lump in my armpit and when they removed it they gave me some terrible news, saying ‘Michael, you have cancer, a bad one, and it doesn’t have a cure.’
“I don’t remember the rest of what I heard because I thought I was in the middle of a nightmare and it wasn’t true.
“They said I had a melanoma. Obviously melanoma normally is not in the armpit, it’’s in the skin. The metastasis had travelled and it showed itself up in my armpit.
“For a couple of days I didn’t really know what day it was. I thought it was a bad dream and in any case I thought it was minor and I would go to the hospital the following day and I’d be told, ‘We’ve made a mistake Michael’."
Then striker, who started his career with Preston, appeared in more than 300 official games in England for five different clubs , including Queens Park Rangers, before three seasons in Spain with Osasuna.