What should you know about lentigo maligna in situ?

In situ means the abnormal melanoma cells are located within the epidermis, the skin's outer layer, rather than having grown into deeper tissue. Lentigo maligna often presents as a flat, unevenly coloured patch on chronically sun-exposed skin, commonly on the face or scalp.

The visible border may be wider than expected, and pigment can extend beyond the most obvious edge. Examination and biopsy help confirm the diagnosis and map the area. This diagnosis is different from invasive melanoma, although untreated in-situ disease can progress into deeper skin.

Follow the treatment plan from a dermatologist or skin-cancer team. Surgical excision is commonly used to remove the lesion with a margin of surrounding skin; specialised skin-cancer surgery may be discussed when borders are difficult to define or tissue preservation matters.

Ask how the wound will be repaired, whether additional tissue checking is needed, and how the scar will be protected. A sentinel lymph node biopsy is generally a discussion for selected situations rather than an automatic part of every in-situ diagnosis.

Arrange prompt review for a flat pigmented patch that enlarges, becomes more irregular, develops new shades or forms a raised, bleeding or crusted area. After treatment, contact the care team for wound separation, increasing redness, pus, fever or bleeding that continues despite pressure.

Ask how the diagnosis was confirmed, whether the entire visible and microscopic margin has been assessed, which operation is recommended and what follow-up is needed. Clarify which symptoms should prompt an earlier review of the treated site or nearby skin.