A black line on your nail (medically known as melanonychia) causes a streak of dark pigmentation that runs along the nail bed ...

But the lines were still there. Kennedy News & Media Tagliamonte went to a dermatologist, who told her the “discoloration at the base of my thumb nail ... this black line in my nail was coming ...

Michelle Tagliamonte, 58, spotted faint black lines on the nail of her her right thumb while getting a manicure in September last year. But when the marks hadn't grown out by her next nail session ...

The black lines (left) on Michelle Tagliamonte's thumb were a sign of cancer.

this black line in my nail was coming from inside the growth plate down from inside my nail.” “The melanoma was in the growth plate [in my thumb] down to my first knuckle,” explains Tagliamonte.