A woman posted a photo of her curved nail on Facebook—and learned it was a sign of cancer

Most people know to schedule an appointment with their doctor ASAP if they feel a strange lump on their breast or neck. But signs of cancer can be less obvious, too—some, like a pimple that doesn’t go away, a hoarse voice, or a “foreign body sensation” in your throat, can seem completely random. Another unexpected symptom to add to that list? Clubbing in the nails, which occurs when fingertips swell and cause the nail to curve downward, and in rare cases could be an early sign of lung cancer.

This is something a woman from the United Kingdom recently learned firsthand. After posting a photo of her curved nail on Facebook and asking if any of her followers “had seen nails like this,” JeanJeannie Williams Taylor‎ was “urged to go to the doctor” to have it looked at more closely. Although Taylor thought this reaction was “a tad extreme,” as she wrote on Facebook, she took their advice. Soon after, she found herself rushed through a series of tests, including bloodwork, a chest X-ray, CT scan, PET scan, MRI scan, and lung biopsy. After what she calls a “grueling” two weeks, Taylor received her diagnosis: cancer in both of her lungs.

Although the average person might not necessarily associate clubbing with potential illness, it’s a well-known red flag in the medical community.