4 Leg Abnormalities Indicating Cancer :

1. Persistent Pain: If leg pain persists and worsens over time, even with treatment, it could be a sign of cancer.

2. Changes in Color:  For instance, melanoma can cause pigmentation changes, raised patches, and itching or pain. Squamous cell carcinoma can also alter leg color. 

3. Abnormal Swelling: Smooth skin is usual, while lumps or bumps on the leg might signal osteosarcoma. 

4. Lower Extremity Edema: Cancer cells invading blood vessels and nerves can lead to swelling and discomfort in the lower extremities.