Naomi Williams, 29, was watching a recent episode of the ABC hospital drama Grey's Anatomy, on which Katherine Heigl's character, Izzy Stevens, is battling advanced skin cancer but had to stop because her own experience with skin cancer was still too fresh to endure seeing it unfold on screen.
"The timing is very surreal," said Williams, who lives in Jacksonville, Fla. "It was really intense... too difficult to watch for me."
Like Heigl's character, Williams was diagnosed with stage 4 melanoma -- the most serious type of skin cancer -- about one month ago. The cancer was discovered after she broke a bone in her back bending down to put a plug in a socket. Subsequent tests revealed that she had cancer in her bones and her lungs.
"That was the red flag that started it all," Williams said of her bone fracture. "The question was, why are you 29 and healthy and having a bone fracture? The diagnosis was malignant melanoma but they can't find anything on my skin to show that it's melanoma."
Undetectable sources of melanoma are not unusual. While the cancer does begin most commonly in moles or other skin discolorations -- since melanoma occurs in the skin's pigment cells or melanocytes -- it can develop in other tissues as well and cause secondary problems that hint at cancer.
The first sign that Heigl's character had a health problem occurred when she began having hallucinations of a romantic interest who had died. Prompted by these hallucinations, the character underwent a series of tests, finally discovering that she had stage 4 metastatic melanoma. The cancer had spread to her liver, as well as to her brain, which explained the hallucinations. In the show, the character's chances of survival are estimated at only 5 percent, which is a typical prognosis for someone with stage 4 metastatic melanoma.
"The sun isn't the only thing that causes melanomas," said Dr. Murad Alam, an associate professor of dermatology at Northwestern University in Chicago. "Sometimes melanoma just happens."
The National Cancer Institute estimates 68,720 new cases of melanoma will develop in 2009, and 8,650 deaths from the cancer.
Alam said that some melanomas can arise in brain tissues or brain-like tissues inside the eye because skin cells can develop from brain cells in babies. These types of melanomas are not visible on the skin. Other types can involve a mole that becomes cancerous and then the colored mole disappears. Amelanotic melanomas are visible on the skin but they are skin-colored or pink, making them hard to spot.
These types of melanomas are often the ones with the worst prognosis, not because they are difficult to treat when caught early, but because they go undetected for so long that they spread to other tissues and develop into more advanced cancers.
Sun exposure does increase a person's risk of developing melanoma but there are several other factors that increase risk including having fair skin and being a 20- or 30-something woman.
In general, the deeper the melanoma is, the more likely it is that a small piece of the cancerous tissue will break off and travel, through the blood or through the lymphatic system, to other tissues, infecting them with cancer.
"Melanoma can metastasize to almost any organ," Alam said. "And then it's not noticed until something happens."
Prior to her diagnosis, Williams had no reason to think anything could go wrong with her body. She was active, running after her two-year-old son, and enjoyed yoga and eating healthfully. She ran a successful photography business. Learning she had cancer, something she said she thought of as an older person's disease, was a shock.
"I didn't realize it could happen to someone so young," Williams said.
But Alam said melanoma is particularly aggressive in young people, striking hard and moving quickly. And while there are a variety of treatment options, there is no reliable therapy when the cancer reaches stage 4.
Williams is undergoing chemotherapy but is exploring a variety of treatment options abroad -- some not approved for use in the U.S. -- if her current treatments stop giving positive results. Right now, Williams said she is focusing on spending time with her husband, son, and friends.
But Williams won't be watching the season finale of Grey's Anatomy tonight.
"I feel a connection [to the character] but it's too new and too fresh," Williams said. "Looking back a year from now and I'm recovered, it might be a different story."
Read more about Naomi Williams at Pictures of Hope.
ABC News' Dan Childs contributed to this report.