LONDON (AP) —

Sarah, the Duchess of York

, has been diagnosed with a malignant skin cancer that was discovered during her

treatment for breast cancer

, a spokesperson said.

The melanoma was found after several moles were removed while she was undergoing reconstructive surgery after a mastectomy. Doctors are analyzing it to see if it was caught early.

“Clearly, another diagnosis so soon after treatment for breast cancer has been distressing but the Duchess remains in good spirits," the spokesperson said.

Sarah, 64, the ex-wife of

Prince Andrew

and the mother of Princess Beatrice and Princess Eugenie was once a favorite target of Britain’s tabloids. The former Sarah Ferguson, known as “Fergie,” has published her memoirs and authored a number of children’s books as well as a historical romance for adults.

The announcement came five days after

dual health announcements

in Britain's royal family. Kate, the Princess of Wales, had abdominal surgery and

King Charles III

is due this week to have prostate treatment.