A Spanish woman today found her "guardian angel" – the stranger who saved her life after approaching her on a bus to say that she was probably suffering from a rare disease caused by a tumour.

Montse Ventura, 55, said the woman who sat opposite her on Barcelona's number 64 bus nine months ago saved her life by advising her to have tests for acromegaly – a disorder resulting from an excess of growth hormone due to a pituitary gland tumour.

She had no idea what the woman was talking about but accepted a piece of paper where the woman had written down the names of two clinical tests.

"She wrote something down and said 'Have the analysis done as soon as possible because if you wait until you feel the need to the consult your doctor, you may already be in a very bad state,'" Ventura said. "A month later I went to my gynaecologist for my annual check-up. I handed over the piece of paper and asked for those tests to be added to the standard ones."

To her doctor's surprise, the test results rang alarm bells. "Some hormonal measures were totally abnormal," she said. "I had more tests done and they ended up operating on a tumour." The operation to remove the tiny tumour from the pea-sized pituitary gland at the base of her brain was successful.

On Tuesday a 60-year-old endocrinologist rang La Vanguardia newspaper to say she had made the diagnosis after seeing Ventura's unusually shaped hands. "The hands gave me a lot of clues but I wasn't sure whether to say anything but I am a very spontaneous person," she explained. "I'd rather put my foot in it than keep the worry to myself."

Ventura and her guardian angel have now spoken by phone and will meet when the media fuss in Spain dies down.