Acral Lentiginous Melanoma (ALM)

Palm or sole

It usually begins as an irregularly shaped tan, brown, or black spot. Sometimes people may think it was caused by a recent injury in the general area of the pigmented spot.

Mucous membranes

Mucous membranes are specialized areas of skin that have a unique lining. Some examples are the mouth, nose, external eyes, and genital openings. Early symptoms of melanoma on these sites include nosebleeds and nasal stuffiness and a pigmented mass inside the mouth. Melanomas also can develop on the mucous membranes of the anus, urinary tract, and female genitalia.

Under a nail

The first sign may be a “nail streak”-a narrow, dark stripe under the nail. ALM usually develops on the thumb or big toe; however, it can occur under any fingernail or toenail. Not all nail streaks are melanoma-many dark-skinned people may have nail streaks that are completely benign.

  • A new nail streak, not caused by a recent accident or trauma, an enlarging nail streak, a wide or very darkly pigmented streak, or a nail that is separating or lifting up from the nail bed should always be examined by a dermatologist.
  • A sign of more advanced ALM is when the nail streak has pigmentation in the nail fold skin or when the nail plate is destroyed.
  • ALM of the fingers or toes also can develop without an obvious nail streak, particularly the nonpigmented variety. ALM may, for example, look very much like a chronic infection of the nail bed.

Other Things to Know About Acral Lentiginous Melanoma

  • As an ALM tumor increases in size, it usually becomes more irregular in shape and color (although some ALM lesions can be lightly colored or colorless).
  • The surface of the ALM lesion may remain flat, even as the tumor invades deeply into the skin.
  • Thickening ALM on the sole of the foot can make walking painful and be mistaken for a plantar wart.

Be sure to see a dermatologist as soon as possible if you notice:

  • A bruise that does not fade or comes and goes
  • A nail that lifts up or separates from the nail bed
  • A new nail streak not associated with recent trauma
  • An enlarging nail streak
  • A wide or very darkly pigmented nail streak
  • A pigmented mass in the mouth
  • Nosebleeds and nasal stuffiness

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