Other conditions that may be confused with melanoma include:

• Seborrheic keratosis.
• Moles with unusual patterns of color and shape.
• Dermatofibroma (round, firm, brown to purple growths often found on the legs and arms).
• Lentigo (brown symmetrical flat spots).
• Basal cell cancer.
• Squamous cell cancer.
• Actinic keratosis.
• Kaposi's sarcoma.
• Spitz nevus (malignant tumors that resemble melanoma but do not progress).
• Hemangioma (noncancerous blood vessel tumors).
• Venous malformation (tangles of small veins).
• Blood blisters that resolve in 7 to 14 days.
• Skin tags.
• Warts.
• Bruises.
• Tattoos.