What should you know about precancerous melanoma?

Precancerous describes abnormal cells that are not yet invasive cancer, while [Melanoma](/conditions/melanoma/) is a cancer arising from pigment-producing cells. A mole or dark patch can change in size, shape, colour, border, or surface; it may also itch, bleed, crust, or develop a new area of pigment. These signs do not determine the diagnosis by themselves. A skin examination and, when needed, biopsy provide the answer. Melanoma can occur in previously normal skin as well as in an existing mole.

Arrange a prompt dermatology appointment for a new or changing pigmented lesion. Do not remove it cosmetically before assessment, because the tissue and its edges may be needed for diagnosis. The clinician may examine the whole skin surface, photograph the area, and recommend [Surgical Excision](/treatments/surgical-dermatology/excisional-surgery/) or [Skin Cancer Surgery](/treatments/surgical-dermatology/skin-cancer-surgery/). If melanoma is confirmed, further planning can involve [Sentinel Lymph Node Biopsy](/treatments/diagnostics-and-staging/sentinel-lymph-node-biopsy/) or other specialist treatment.

Seek prompt review for a lesion that changes quickly, has an irregular outline, shows several colours, repeatedly bleeds, forms a persistent crust, or differs clearly from your other moles. Arrange urgent care for uncontrolled bleeding, rapidly spreading redness, severe pain, or a rapidly enlarging lesion. New neurological symptoms in someone already diagnosed with melanoma, such as weakness, confusion, seizure, or a severe new headache, require emergency assessment.

What changes do you see, and does the lesion need a biopsy? If melanoma is found, what stage information is needed? Which treatment and follow-up plan apply to my result?