Jimmy Buffett's cause of death revealed to be Merkel cell cancer, a rare form of skin cancer

Singer Jimmy Buffett, who died Friday at the age of 76, battled skin cancer for years before his death, according to a statement on his website.

Buffet suffered from Merkel cell cancer, the website said. 

Merkel cell cancer is very rare, according to the National Cancer Institute. Risk factors include sun exposure, having a weak immune system and being older than 50. It tends to grow quickly and spread at an early stage to nearby lymph nodes and then to lymph nodes or skin in other parts of the body, including the lungs, brain, bones and other organs. 

Buffet continued to perform during his treatment. His last show was a surprise appearance in Rhode Island in early July, according to his website.

Key West, Florida, honored Buffett with a parade Sunday evening, CBS News Miami reports. Buffett was a longtime resident of the island.

In 2022, Buffett rescheduled tour dates because of health issues and a "brief hospitalization." Those tour dates were meant to take place at the end of 2022 and were rescheduled for 2023. In May, he canceled a South Carolina concert after being hospitalized.

"Growing old is not for sissies, I promise you," he said at the time. 

Buffett died at his home in Sag Harbor, New York, according to his website. He was surrounded by family and friends at the time. 

The "Margaritaville" singer is survived by his wife, Jane Slagsvol, two daughters, Savannah Jane and Sarah Delaney, and son Cameron Marley.