Woman shares warning on TikTok after nail streak was more than a mole

For years, Maria Sylvia didn't think she needed to get a straight, brown streak that had appeared on her right thumbnail tested.

The 25-year-old shared what it looked like in a TikTok video last month and wrote, "me: having this for 10 years, thinking it was a cool streak on my nail."

In the next frame, she continued, "it's cancer."

Sylvia told "Good Morning America" the diagnosis was completely unexpected and only came about after a friend urged her to consult a doctor about her unusual nail discoloration.

"When he told me that, you know, 'Oh, we found melanoma, you know, my heart dropped,'" Sylvia recalled of her January conversation with a dermatologist. "He was rattling off phone numbers that I had to call and I'm still like grasping that I just found out that I had cancer."

In Sylvia's case, the doctor informed her she has subungual melanoma, which often affects the fingernail or toenail. Subungual melanoma is also a form of acral lentigionus melanoma, a skin cancer that doesn't appear to be caused by sunlight and makes up less than 5% of melanoma cases worldwide. The average age of diagnosis is typically between 60 and 70 years old but these melanomas can develop in anyone and are the most common form of melanoma in Hispanic, Black and Asian populations, according to the National Institutes of Health.

"If you're catching it early, it can be totally asymptomatic, meaning that you feel no pain," dermatologist Dr. Whitney Bowe told "GMA." "You don't want a lesion to become painful, start to bleed, or start to create any kind of deformity of the nail. That usually means that we're catching it too late."

In a follow-up video, Sylvia said she had seen doctors in the past and one had suggested her nail discoloration could be a mole.

Sylvia encouraged others who may be concerned to go see a doctor. "You really have to be your advocate here and say, 'No, no, I'd really like to get a biopsy just to be sure,'" she told "GMA."

Following her diagnosis, Sylvia said in another TikTok video that she found out the melanoma had not appeared to spread. She has since underwent surgery and a skin graft.

Since opening up on TikTok, Sylvia has heard from others who said her warning video has been eye-opening and helpful.

"I saw this TikTok a couple weeks ago and really thought nothing of it until I saw my mom's toe and was really concerned. She got an appointment, and long story short, you saved my mom's life. Thank you," posted one TikTok user.

Bowe also encourages anyone who wears nail polish to remove it at least once a month and inspect the nails for any abnormalities like pigmentation or discoloration.