The 'cure' has become the 69th such miracle to take place at the shrine in the south of France, French newspaper Le Point reported, citing AFP.
Danila Castelli, from Pavia in northern Italy, visited the shrine in 1989, and after emerging from the baths felt “an extraordinary feeling of wellbeing,” the report said.
The event was recognised as a miracle in June by Giovanni Giudici, the bishop of Pavia. However, severe flooding in the area prevented the news from being announced.
Castelli is reported to have started suffering from hypertension - sudden, brutal rises in blood pressure - when she was 34.
Further tests also revealed a tumour in her urogenital system. She was operated on several times, but without success.
After the trip to Lourdes in May 1989, she reported her apparent cure to the Lourdes Office of Medical Observations.
After five meetings between 1989 and 2010, the office concluded that “Mrs Castelli was cured, in a complete and lasting way, from the date of her pilgrimage to Lourdes - 21 years ago - of the syndrome she had suffered and without any relation to the treatments and the surgeries she underwent.”
The case was passed on to the Lourdes International Medical Committee, which counts some 20 doctors and which certified that the way she healed remains "unexplained according to current scientific knowledge".
This is the 69th such miracle attributed to Lourdes since the late 1850s.
The 68th was that of an Italian nun who had been paralysed for years and started walking after a pilgrimage to Lourdes in 1965. Her case was officially recognised as a miracle last year.