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For further information, see CMDT Part 6-08: Malignant Melanoma

Key Features

Essentials of Diagnosis

  • May be flat or raised with irregular borders

  • Examination may show varying colors, including red, white, black, and blue

  • Should be suspected in any pigmented skin lesion with recent change in appearance

  • Less than 30% develop from existing moles

General Considerations

  • Leading cause of death due to skin disease and fifth most common cancer

  • Primary malignant melanomas may be classified into various clinicohistologic types

    • Lentigo maligna melanoma (arising on chronically sun-exposed skin of older individuals)

    • Superficial spreading malignant melanoma (two-thirds of all melanomas arising on intermittently sun-exposed skin)

    • Nodular malignant melanoma

    • Acral-lentiginous melanomas (arising on palms, soles, and nail beds)

      • Diagnosis may be difficult or delayed because benign pigmented lesions in these areas occur commonly in more darkly pigmented persons; clinicians may hesitate to biopsy the palms and especially the soles and nail beds

      • Clinicians should give special attention to new or changing lesions in these areas

    • Malignant melanomas on mucous membranes


  • One in four cases of melanoma occur before the age of 40

  • In 2021, approximately 106,110 new melanomas were diagnosed in the United States, approximately 60% in men

  • Each year melanoma causes an estimated 7180 deaths (two-thirds in men)

  • Lifetime risk is 2% in White and 0.1–0.5% in non-White individuals

Clinical Findings

Symptoms and Signs

  • An irregular notched border where the pigment appears to be leaking into the normal surrounding skin

  • Topography may be irregular, ie, partly raised and partly flat

  • Color variegation, and colors such as pink, blue, gray, white, and black are indications for referral

  • Bleeding and ulceration

  • A mole that stands out from the patient's other moles (the "ugly duckling sign")

  • A patient with a large number of moles is at increased risk for melanoma

  • The history of a changing mole (evolution) is the single most important historical reason for close evaluation and possible referral

  • Acral lentiginous melanomas: dark, sometimes irregularly shaped lesions on the palms and soles and new, often broad and solitary, darkly pigmented longitudinal streaks in the nails

Differential Diagnosis

  • Acquired nevus (mole), eg, junctional nevus, compound nevus

  • Seborrheic keratosis

  • Lentigo, eg, solar lentigo

  • Dermatofibroma

  • Basal cell carcinoma (pigmented type)

  • Congenital nevus

  • Atypical (dysplastic) nevus

  • Blue nevus

  • Halo nevus

  • Pyogenic granuloma

  • Kaposi sarcoma

  • Pregnancy-associated darkening of nevi


  • Skin biopsies



  • Treatment starts with complete excision with a negative wide margin

    • After histologic diagnosis, reexcision is recommended with margins dictated by the thickness of the tumor

    • Recommended surgical margins are

      • 0.5–1 cm for melanoma in situ

      • 1 cm for lesions < 1 ...

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