The duchess underwent an eight-hour mastectomy in July last year

Sarah Ferguson, Duchess of York, has been diagnosed with malignant melanoma, an aggressive form of skin cancer, just months after she was treated for breast cancer, the Guardian reported. The 64-year-old's spokesperson informed that the disease was detected after several moles were removed when she was treated for breast cancer in June.

''Following her diagnosis with an early form of breast cancer this summer, Sarah, Duchess of York, has now been diagnosed with malignant melanoma. Her dermatologist asked that several moles be removed and analysed at the same time as the duchess was undergoing reconstructive surgery following her mastectomy, and one of these has been identified as cancerous,'' her spokesperson said. 

Doctors are currently assessing whether the melanoma was detected in its early stages. "She is undergoing further investigations to ensure that this has been caught in the early stages. Another diagnosis so soon after treatment for breast cancer has been distressing but the Duchess remains in good spirits,'' her spokesperson added. 

The spokesperson further said that the Duchess wanted to encourage everyone to remember the importance of checking the size, shape, color, and texture and emergence of new moles. Melanoma can be treated successfully if it is found early, according to the Mayo Clinic. 

Notably, the duchess underwent an eight-hour mastectomy in July last year after being diagnosed with breast cancer. 

Ms Ferguson, who used to be married to Prince Andrew, is mother to Princesses Beatrice and Eugenie of York. Affectionately known in Britain as "Fergie", she still shares a manor near Windsor Castle with Prince Andrew. He has stepped down from royal duties following a sex abuse scandal linked to the late US sex offender Jeffrey Epstein.

While the Duchess of York stopped being a working royal after her divorce from Prince Andrew in 1996, she continues to champion charities privately via her organization Sarah's Trust.

Meanwhile, the news of the diagnosis comes as King Charles prepares to undergo treatment for an enlarged prostate, while the Princess of Wales is recovering in hospital after abdominal surgery.