Basal Cell Carcinoma: Signs, Diagnosis and Treatment

Basal cell carcinoma is a slow-growing skin cancer that usually begins on sun-exposed skin and needs medical assessment and treatment.

It develops from basal cells in the outer layer of skin. It often grows locally rather than spreading to distant organs, but untreated growth can damage nearby skin, cartilage, bone or nerves. Early assessment can make removal simpler and preserve more healthy tissue.

Basal cell carcinoma very commonly presents as a sore that repeatedly crusts, bleeds or does not heal. It may also appear as a shiny or pearly bump, a flat scaly patch, a scar-like area, or an ulcer with a raised edge. Colour can be pink, red, brown, black or close to the surrounding skin.

A new or changing lesion deserves examination, especially when it bleeds with minor contact or returns after seeming to heal. Seek prompt care for heavy bleeding, rapidly increasing swelling, severe pain, or a lesion near the eye that affects vision.

Damage to DNA in basal cells allows them to multiply abnormally. Ultraviolet radiation from sunlight and tanning devices is the main driver. Damage accumulates over time, so a tumour may become visible long after the exposures that contributed to it.

A person cannot catch basal cell carcinoma from someone else. Ordinary touching, sharing towels and close contact do not transmit it.

Growth is often gradual, and the lesion may alternate between crusting and partial healing. Without treatment it can widen, deepen and invade nearby structures. Tumours on the eyelid, nose, ear or lip can cause significant local damage because important structures are close together.

A treated person can later develop another basal cell carcinoma in a different area. Follow-up focuses on the treated site, the rest of the skin and any new change the person has noticed.

Risk rises with repeated ultraviolet exposure, a history of sunburn, fair skin that burns easily, outdoor work, tanning-device use and previous skin cancer. Medicines or illnesses that suppress immune function can also increase susceptibility. Basal cell carcinoma can occur in any skin tone, and darker lesions may be mistaken for other marks.

A dermatologist asks when the change appeared, whether it bleeds or heals, and about previous sun exposure and skin cancers. The clinician examines the lesion and surrounding skin, sometimes using a handheld magnifying device called a dermatoscope.

Confirmation generally requires a biopsy. After numbing the area, the clinician removes part or all of the lesion for examination under a microscope. The pathology report identifies the tumour pattern and helps guide the treatment margin and method.

Treatment depends on the tumour's location, size, borders, microscopic pattern, whether it has returned and the person's general health. Surgical excision removes the visible tumour with a margin of surrounding skin. Mohs surgery removes tissue in stages and checks each layer under a microscope, which can help conserve healthy tissue at sensitive sites or manage higher-risk tumours.

Selected superficial tumours may be treated with prescription imiquimod or photodynamic therapy. Radiotherapy can be considered when surgery is unsuitable or would be especially difficult. These approaches are not interchangeable; the clinician explains expected clearance, wound care, scarring and follow-up for the specific lesion.

Follow the wound-care instructions supplied after a biopsy or treatment. Keep dressings clean, avoid picking crusts and report increasing warmth, pus, worsening pain or spreading redness. Once the wound has closed, sun protection helps protect the scar and surrounding skin.

Check the skin regularly in good light, including the scalp, ears and back. Photographs can help track a spot that is difficult to remember, but they do not replace an examination when a lesion is changing.

Local invasion can create an open wound, bleeding, infection, numbness or damage to nearby tissue. Treatment may leave a scar or alter the contour of an ear, nose or eyelid. Recurrence at the treated site is possible, so a persistent new bump, ulcer or bleeding point in or beside a scar warrants review.

Use shade, protective clothing, a broad-brimmed hat and sunglasses when ultraviolet exposure is strong. Apply broad-spectrum sunscreen generously to exposed skin and reapply after swimming, sweating or towelling. Avoid tanning devices and plan outdoor tasks away from the strongest sunlight when practical.

A dermatologist can assess a suspicious lesion and arrange biopsy. Depending on the site and treatment plan, care may also involve a Mohs surgeon, plastic surgeon, ophthalmic specialist or radiation oncologist. Bring a medicine list, prior pathology reports and photographs showing change over time.