3. Changes in the Fingernails
The thumbnail in the image draws attention to a dark vertical line beneath the nail.
A dark streak in a nail can have several causes.
One possibility, although relatively uncommon, is subungual melanoma, a form of melanoma that develops beneath the nail.
Warning features can include a new dark band that becomes wider or changes over time, especially when pigmentation extends onto the surrounding skin.
However, nail discoloration can also result from trauma, fungal infection, medications, pigmentation differences, or other benign conditions.
For that reason, a dark streak should not automatically be labeled cancer based on appearance alone.
If a new pigmented streak appears and persists—or particularly if it changes—have it evaluated by a dermatologist.
4. Persistent Swelling or an Unexplained Lump
A lump or swelling anywhere on the body can be alarming.
Fortunately, many lumps are benign. Cysts, infections, lipomas, enlarged lymph nodes, and other noncancerous conditions are common causes.
Still, a lump deserves medical attention when it:
- Continues growing
- Feels unusually firm
- Does not resolve
- Is fixed rather than easily movable
- Is accompanied by unexplained weight loss
- Occurs together with persistent fever or night sweats
A lump cannot reliably be identified as cancer simply by touching it.
Doctors may use physical examination, ultrasound, imaging, blood tests, or sometimes a biopsy to determine what is causing it.
5. Unexplained Weight Loss
One of the broader symptoms associated with several cancers is unintentional weight loss.