Can you help please!
I am trying to find out the title of an old American Sci-Fi movie. It was made in the 1950/60's, and was in black&white. The short description I have of the film is:

It involves a man who has returned from space, who then over a period starts to transform into a scary looking human monster, with parts of his body gradually being replaced by a thick mass, until he is completely covered.

It is not 'First Man into Space'

Hope someone may have an idea, thanks from England U.K. :)

Sounds Like it might have been The Quatermass Xperiment