Irish-American dancer Michael Flatley has undergone surgery for an "aggressive" form of cancer and is under medical care, a statement on the "Lord of the Dance" creator's Instagram account said.  Flatley, 64, rose to fame as a lead member of the "Riverdance" troupe, whose show-stopping performance at the 1994 Eurovision Song Contest propelled Irish dancing into the global spotlight. He later opened his own "Lord of the Dance" show.  "Michael Flatley has been diagnosed with an aggressive form of cancer. He has undergone surgery and is in the care of an excellent team of doctors. No further comments will be made at this time," the statement released late on Wednesday said.  Flatley has previously said that he was diagnosed with a malignant melanoma in 2003.  Flatley, born in Chicago to Irish-American parents, most recently wrote, directed and starred in the action film "Blackbird", which was released in cinemas last year, four years after its completion.