Acral lentiginous melanoma
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|Acral lentiginous melanoma|
|Classification and external resources|
|ICD-10||C43 (ILDS C43.L60)|
About 1 to 3% of melanomas in Australia and New Zealand are acral lentiginous melanoma. Melanoma is a potentially serious skin cancer that arises from pigment cells (melanocytes). Although acral lentiginous melanoma is rare in Caucasians and people with lighter skin types, it is the most common subtype in people with darker skins. Acral lentiginous melanoma is observed on the palms, soles, under the nails and in the oral mucosa. It occurs on non hair-bearing surfaces of the body which may or may not be exposed to sunlight. It is also found on mucous membranes. Unlike other forms of melanoma, acral lentiginous melanoma does not appear to be linked to sun exposure.
It is the most common form of melanoma diagnosed amongst Asian and Black ethnic groups. The average age at diagnosis is between sixty and seventy years. However, the melanoma can also occur in White ethnic groups and in young people.
Even though the ideal method of diagnosis of melanomas should be complete excisional biopsy, the location of the melanoma may require alternatives.
Dermatoscopy of acral pigmented lesions is very difficult, but can be accomplished with diligent attention.
Initial confirmation of the suspicion can be done with a small wedge biopsy or small punch biopsy. Thin deep wedge biopsies can heal very well on acral skin, and small punch biopsies can give enough clue to the malignant nature of the lesion. Once this confirmatory biopsy is done, a second complete excisional skin biopsy can be performed with a narrow surgical margin (1 mm). This second biopsy will determine the depth and invasiveness of the melanoma, and will help to define what the final treatment will be. If the melanoma involves the nail fold and the nail bed, complete excision of the nail unit might be required.
Final treatment might require wider excision (margins of 0.5 cm or more), digital amputation, lymphangiogram with lymph node dissection, or chemotherapy.
Signs and symptoms
Typical signs of acral lentiginous melanoma include:
- longitudinal tan, black, or brown streak on a finger or toe nail (melanonychia striata)
- pigmentation of proximal nail fold
- areas of dark pigmentation on palms of hands or soles of feet
Warning signs are new areas of pigmentation, or existing pigmentation that shows change. If caught early, acral lentiginous melanoma has a similar cure rate as the other types of superficial spreading melanoma.
Histological signs of acral lentiginous melanoma include:
- Phan A, Touzet S, Dalle S, Ronger-Savlé S, Balme B, Thomas L (August 2007). "Acral lentiginous melanoma: histopathological prognostic features of 121 cases". Br. J. Dermatol. 157 (2): 311–8. doi:10.1111/j.1365-2133.2007.08031.x. PMID 17596173.
- James, William D.; Berger, Timothy G.; et al. (2006). Andrews' Diseases of the Skin: clinical Dermatology. Saunders Elsevier. ISBN 0-7216-2921-0.
- Krementz ET, Feed RJ, Coleman WP, Sutherland CM, Carter RD, Campbell M (May 1982). "Acral lentiginous melanoma. A clinicopathologic entity". Ann. Surg. 195 (5): 632–45. doi:10.1097/00000658-198205000-00013. PMC 1352575. PMID 7073361.
- "His story: The life and legacy of Bob Marley". web.bobmarley.com. Retrieved October 4, 2009.