Acral lentiginous melanoma
Encyclopedia
Acral lentiginous melanoma is a kind of lentiginous skin cancer skin melanoma
.
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 Caucasians
and in young people.
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.
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.
There are often no symptoms for melanoma
until it is well advanced.
's death was caused by acral lentiginous melanoma present under one of his toenails.
Melanoma
Melanoma is a malignant tumor of melanocytes. Melanocytes are cells that produce the dark pigment, melanin, which is responsible for the color of skin. They predominantly occur in skin, but are also found in other parts of the body, including the bowel and the eye...
.
Acral lentiginous melanoma is observed on the palms, soles, under the nails and in the oral mucosa
Oral mucosa
The oral mucosa is the mucous membrane epithelium of the mouth. It can be divided into three categories.*Masticatory mucosa, para-keratinized stratified squamous epithelium, found on the dorsum of the tongue, hard palate and attached gingiva....
. 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
Asian people
Asian people or Asiatic people is a term with multiple meanings that refers to people who descend from a portion of Asia's population.- Central Asia :...
and Black
Black people
The term black people is used in systems of racial classification for humans of a dark skinned phenotype, relative to other racial groups.Different societies apply different criteria regarding who is classified as "black", and often social variables such as class, socio-economic status also plays a...
ethnic groups. The average age at diagnosis is between sixty and seventy years. However, the melanoma can also occur in Caucasians
Caucasian race
The term Caucasian race has been used to denote the general physical type of some or all of the populations of Europe, North Africa, the Horn of Africa, Western Asia , Central Asia and South Asia...
and in young people.
Diagnosis
Even though the ideal method of diagnosis of melanomas should be complete excisional biopsy, the location of the melanoma may require alternatives.Dermatoscopy
Dermatoscopy
Dermatoscopy is the examination of skin lesions with a dermatoscope...
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
Skin biopsy
Skin biopsy is a biopsy technique in which a skin lesion is removed and sent to the pathologist to render a microscopic diagnosis. It is usually done under local anesthetic in a physician's office, and results are often available in 4 to 10 days. It is commonly performed by dermatologists. Skin...
can be performed with a narrow surgical margin (1 mm). This second biopsy will determine the depth and invasiveness of the melanoma
Melanoma
Melanoma is a malignant tumor of melanocytes. Melanocytes are cells that produce the dark pigment, melanin, which is responsible for the color of skin. They predominantly occur in skin, but are also found in other parts of the body, including the bowel and the eye...
, 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.
There are often no symptoms for melanoma
Melanoma
Melanoma is a malignant tumor of melanocytes. Melanocytes are cells that produce the dark pigment, melanin, which is responsible for the color of skin. They predominantly occur in skin, but are also found in other parts of the body, including the bowel and the eye...
until it is well advanced.
Histology
Histological signs of acral lentiginous melanoma include:- atypical melanocyteMelanocyte-External links: - "Eye: fovea, RPE" - "Integument: pigmented skin"...
s arranged singly and in junctional nests - dermal invasion
- desmoplasiaDesmoplasiaIn medicine, a desmoplastic fibroma is a benign fibrous tumour of bone, affecting children and young adults, potentially resulting in cortical bone destruction. It can also occur in the hand....
Famous cases
Bob MarleyBob Marley
Robert Nesta "Bob" Marley, OM was a Jamaican singer-songwriter and musician. He was the rhythm guitarist and lead singer for the ska, rocksteady and reggae band Bob Marley & The Wailers...
's death was caused by acral lentiginous melanoma present under one of his toenails.