Melanoma

Early diagnosis is vital to outcome. Thickness of a melanoma when it is removed is the major factor determining prognosis: it is vital to detect melanomas when they are in the thin stage and look like an unusual freckle. An irregular border or margin is characteristic of the tumour.

Clinical features

• Typical age range 30–50 yrs (av. 40)

• Can occur anywhere on the body. More common:

  • – lower limb in women

  • – upper back in men

• Often asymptomatic

• Can bleed or itch

Change The sign of major importance is a recent change in a ‘freckle’ or mole:

• change in size: at edge or thickening

• change in shape

• change in colour: brown, blue, black, red, white, incl. combinations

• change in surface

• change in the border

• bleeding or ulceration

• other symptoms (e.g. itching)

• development of satellite nodules

• lymph node involvement

Beware of the non-pigmented melanoma, esp. on the sole of the foot.

Pitfalls/traps in diagnosis

• Nodular melanomas

• Small melanoma

• Amelanotic melanoma

• Regressing melanoma

• Rapidly growing melanoma

The early nodular melanoma problem The ABCD rule often does not apply. Early nodular melanomas tend to be symmetrical, non-pigmented, even in colour, small diameter, firm and grow vertically, i.e. elevated. They are often mistaken for a haemangioma or a pyogenic granuloma. Refer if suspicious.

Management

• Early diagnosis and referral to specialist unit is vital.

• Surgical excision with a narrow but significant margin is the treatment.

• Guidelines for excision margins:

  • – suspicious lesion—margin 2 mm

  • – melanoma in situ—margin 5–10 mm

  • – melanoma <1 mm thick—margin 1 cm

    1–4 mm thick—margin 1–2 cm

    >4 mm thick—margin 2 cm

• Follow-up is based on the tumour thickness:

  • – ≤1 mm—6 mthly for 2 yrs

  • – >1 mm—regularly for 10 yrs

  • – yearly chest X-ray.