Acral lentiginous melanoma explained

Acral lentiginous melanoma
Symptoms:Areas of dark pigmentation
Causes:Malignant melanocytes
Diagnosis:Biopsy
Treatment:Biologic immunotherapy agents
Frequency:Males = Females

Acral lentiginous melanoma (ALM) is a type of skin cancer.[1] It typically begins as a uniform brownish mark before becoming darker and wider with a blurred, irregular border. ALM is most frequently seen on the foot of a person with darker skin but can also be found in non-sun exposed areas such as the palms, soles, and under finger and toenails.[1] It may become bumpy and ulcerate.[1] When under the nail it typically appears as dark longitudinal streaks. As it grows, ALM may also spread to other areas of the body.

Melanoma is a group of serious skin cancers that arise from pigment cells (melanocytes); acral lentiginous melanoma is a kind of lentiginous[2] skin melanoma.[1] ALM makes up less than 5% of all melanomas, but is considered the most common subtype in people with darker skin and is rare in people with lighter skin types. It is not caused by exposure to sunlight or UV radiation, and wearing sunscreen does not protect against it. It occurs on non-hair-bearing surfaces of the body, which have not necessarily been exposed to sunlight. It is also found on mucous membranes.[3]

Epidemiology

The absolute incidence of ALM is the same for people of all skin colors, and has not changed significantly for decades. However, because rates of other melanomas are low in non-white populations, ALM is the most common form of melanoma diagnosed amongst Asian and sub-Saharan African ethnic groups.[4] The average age at diagnosis is between sixty and seventy years.[5] Males and females are affected equally, but females tend to be diagnosed at earlier stages.

Signs and symptoms

Typical signs of acral lentiginous melanoma include the following [6]

Other uncommon presentations can include:

Warning signs are new areas of pigmentation, or existing pigmentation that shows change. If caught early, ALM has a similar cure rate as the other types of superficial spreading melanoma.[8] In contrast to cutaneous melanoma which utilizes the ABCDE rule (Asymmetry, Border, Color, Diameter, Evolving) to help identify lesions suspicious for skin cancer, an alternative pneumonic CUBED (Colored lesion, Uncertain diagnosis, Bleeding lesion, Enlargement of the lesion, Delay in healing) has been proposed for ALM based on the differences in signs and presentations between the two cancers.[9]

ALM can also cause other non-specific symptoms if it spreads to certain areas of the body:

Causes

Acral lentiginous melanoma is a result of malignant melanocytes at the membrane of the skin (outer layers).[10] [11] The pathogenesis of ALM remains unclear, however injury or mechanical stress might play a role in its development.[12] [13] Unlike cutaneous melanoma, it is not caused by sunlight or UV radiation.

Diagnosis

Although the ideal method of diagnosis of melanoma is complete excisional biopsy,[14] alternative methods may be required based on the location of the melanoma. Dermatoscopy of acral pigmented lesions is very difficult but can be accomplished with diligent focus. Initial confirmation of the suspicion can be done with a small wedge biopsy or small punch biopsy.[15] Thin deep wedge biopsies can heal very well on acral skin, and small punch biopsies may provide enough information to suggest if a lesion is cancerous. 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,[16] and will help to guide further treatment if necessary. In order to establish the Breslow's depth of the lesion, the most raised section of the pigmented area should be sampled.[17] If the melanoma involves the nail fold or the nail bed, complete excision of the nail unit might be required for accurate sampling.

In the event that the melanoma spreads to other sites such as the lymph nodes, another biopsy called the Sentinel lymph node biopsy may provide more information in terms of outcomes. More extensive melanomas may require wider excision (margins of 0.5 cm or more), digital amputation, lymphangiogram with lymph node dissection, or chemotherapy.[18]

Histology

The main characteristic of acral lentiginous melanoma is continuous proliferation of atypical melanocytes at the dermoepidermal junction.[19] Other histological signs of acral lentiginous melanoma include dermal invasion and desmoplasia.[20] This invasion usually occurs many years after the initial lesion first appears.

According to Scolyer et al.,[21] ALM "is usually characterized in its earliest recognisable form as single atypical melanocytes scattered along the junctional epidermal layer".

Treatment

The mainstay of treatment of acral lentiginous melanoma is wide local excision. If metastatic, biologic immunotherapy agents like ipilimumab, pembrolizumab, and nivolumab; BRAF inhibitors, such as vemurafenib and dabrafenib; or a MEK inhibitor trametinib may be used.[22]

When arising in the nailbed of a digit, the evidence suggests that digit-sparing surgery (wide excision and grafting) has similar outcomes to amputation,[23] therefore, to preserve function and aesthetics it is recommended that clinicians default to digit-sparing surgery. Secondary amputation may be considered if the surgery margins are not clear of cancerous cells, or if patients develop a recurrence of the melanoma.

Prognosis

The prognosis of acral lentiginous melanoma is based on multiple factors including gender, age, race, Breslow depth, staging, and sentinel lymph node positivity. Out of these factors, it is believed that sentinel lymph node positivity provides the strongest prediction of cancer recurrence and death.[24] [25] When compared to cutaneous malignant melanoma (CMM), ALM has a poorer prognosis in terms of survival rates.[26] This poorer prognosis is thought to be related to the fact that ALM is usually diagnosed at a later stage than other skin cancers; which may be due to ALM occurring on areas of the body that are harder to notice, especially in the elderly population.

Prevention

Since acral lentiginous melanoma is not linked to sun or UV exposure and the cause is not well-understood, there are no specific preventative measures. However, Patient education can be geared towards populations in which ALM is more common to increase awareness of the warning signs of ALM and other melanomas to help with earlier detection.[27] Early detection is one of the most important factors in disease-specific survival.

Differential Diagnoses

Other benign skin lesions that may mimic acral lentiginous melanoma include: Lentigo (sun spots), Acral Nevi (moles), or Onychomycosis (fungal infection of the nail). These skin lesions can appear as dark brown spots, like ALM, but can be distinguished on close examination or dermatoscopy. Other types of skin cancers like squamous cell carcinoma can also present similarly to ALM.

Society and culture

Jamaican musician Bob Marley died of the condition in 1981, at the age of 36.[28]

See also

Further reading

Notes and References

  1. Book: James . William D. . Andrews' Diseases of the Skin: Clinical Dermatology . Elston . Dirk . Treat . James R. . Rosenbach . Misha A. . Neuhaus . Isaac . 2020 . Elsevier . 978-0-323-54753-6 . 13th . Edinburgh . 696–697 . en . 30. Melanocytic nevi and neoplasms . https://books.google.com/books?id=UEaEDwAAQBAJ&pg=PA696.
  2. Phan . A. . Touzet . S. . Dalle . S. . Ronger-Savlé . S. . Balme . B. . Thomas . L. . Acral lentiginous melanoma: histopathological prognostic features of 121 cases . British Journal of Dermatology . August 2007 . 157 . 2 . 311–318 . 10.1111/j.1365-2133.2007.08031.x . 17596173 . 40412082 .
  3. Book: LeBoit, Philip E. . Pathology and Genetics of Skin Tumours . 2006 . IARC . 978-92-832-2414-3.
  4. Book: Farage, Miranda A. . Textbook of Aging Skin . 2010-01-22 . Springer Science & Business Media . 978-3-540-89655-5 . 2020-12-06 . https://web.archive.org/web/20230111224600/https://books.google.com/books?id=9-ALWZhXomAC&q=Acral+lentiginous+melanoma+ethnic+groups&pg=PA558 . 2023-01-11 . live.
  5. Book: Swartz, Mark H. . Textbook of Physical Diagnosis: History and Examination . 2014-01-07 . Elsevier Health Sciences . 978-0-323-22507-6 . 2020-12-06 . https://web.archive.org/web/20230111224600/https://books.google.com/books?id=Kse7AgAAQBAJ&q=Acral+lentiginous+melanoma++age+of+diagnosis&pg=PA104 . 2023-01-11 . live.
  6. Book: Goodheart, Herbert P. . Goodheart's Same-site Differential Diagnosis: A Rapid Method of Diagnosing and Treating Common Skin Disorders . 2010-10-25 . Lippincott Williams & Wilkins . 978-1-60547-746-6.
  7. Choi . Yoo Duk . Chun . Seung Min . Jin . Sun A. . Lee . Jee-Bum . Yun . Sook Jung . November 2013 . Amelanotic acral melanomas: clinicopathological, BRAF mutation, and KIT aberration analyses . Journal of the American Academy of Dermatology . 69 . 5 . 700–707 . 10.1016/j.jaad.2013.06.035 . 1097-6787 . 23972510.
  8. Book: Hearing . Vincent J. . From Melanocytes to Melanoma: The Progression to Malignancy . Leong . Stanley P. L. . 2007-11-05 . Springer Science & Business Media . 978-1-59259-994-3.
  9. Darmawan . Claudia C. . Jo . Gwanghyun . Montenegro . Sara E. . Kwak . Yoonjin . Cheol . Lee . Cho . Kwang Hyun . Mun . Je-Ho . September 2019 . Early detection of acral melanoma: A review of clinical, dermoscopic, histopathologic, and molecular characteristics . Journal of the American Academy of Dermatology . 81 . 3 . 805–812 . 10.1016/j.jaad.2019.01.081 . 1097-6787 . 30731177.
  10. Book: Brown . Kimberly M. . Melanoma . Chao . Celia . 2014 . Elsevier Health Sciences . 978-0-323-32683-4 . 2020-12-06 . https://web.archive.org/web/20230111224600/https://books.google.com/books?id=OjwHBgAAQBAJ&q=Acral%252520lentiginous%252520melanoma%252520causes&pg=PA1116 . 2023-01-11 . live.
  11. Piliang . Melissa Peck . June 2011 . Acral Lentiginous Melanoma . Clinics in Laboratory Medicine . 31 . 2 . 281–288 . 10.1016/j.cll.2011.03.005 . 21549241.
  12. Basurto-Lozada . Patricia . Molina-Aguilar . Christian . Castaneda-Garcia . Carolina . Vázquez-Cruz . Martha Estefania . Garcia-Salinas . Omar Isaac . Álvarez-Cano . Alethia . Martínez-Said . Héctor . Roldán-Marín . Rodrigo . Adams . David J. . Possik . Patricia A. . Robles-Espinoza . Carla Daniela . January 2021 . Acral lentiginous melanoma: Basic facts, biological characteristics and research perspectives of an understudied disease . Pigment Cell & Melanoma Research . 34 . 1 . 59–71 . 10.1111/pcmr.12885 . 1755-148X . 7818404 . 32330367.
  13. Huang . Kai . Fan . Ji . Misra . Subhasis . July 2020 . Acral Lentiginous Melanoma: Incidence and Survival in the United States, 2006-2015, an Analysis of the SEER Registry . The Journal of Surgical Research . 251 . 329–339 . 10.1016/j.jss.2020.02.010 . 1095-8673 . 32208196.
  14. Book: Shea . Christopher R. . Pathology of Challenging Melanocytic Neoplasms: Diagnosis and Management . Reed . Jon A. . Prieto . Victor G. . 2014-11-03 . Springer . 978-1-4939-1444-9 . 2020-12-06 . https://web.archive.org/web/20230111224602/https://books.google.com/books?id=kuosBQAAQBAJ&q=Acral+lentiginous+melanoma++biopsy&pg=PA166 . 2023-01-11 . live.
  15. Book: ChB . David E. Elder MB . Superficial Melanocytic Pathology . PhD . Sook Jung Yun MD . 2014-11-10 . Demos Medical Publishing . 978-1-62070-023-5 . 2020-12-06 . https://web.archive.org/web/20230111224600/https://books.google.com/books?id=_suRBQAAQBAJ&q=Acral+lentiginous+melanoma++small+punch+biopsy&pg=PA153 . 2023-01-11 . live.
  16. Book: 10.1007/978-3-642-38385-4 . Pathology of Melanocytic Nevi and Melanoma . 2014 . 978-3-642-38384-7 . Barnhill RL, Piepkorn MW, Busam KJ .
  17. Swetter . Susan M. . Tsao . Hensin . Bichakjian . Christopher K. . Curiel-Lewandrowski . Clara . Elder . David E. . Gershenwald . Jeffrey E. . Guild . Valerie . Grant-Kels . Jane M. . Halpern . Allan C. . Johnson . Timothy M. . Sober . Arthur J. . Thompson . John A. . Wisco . Oliver J. . Wyatt . Samantha . Hu . Shasa . January 2019 . Guidelines of care for the management of primary cutaneous melanoma . Journal of the American Academy of Dermatology . 80 . 1 . 208–250 . 10.1016/j.jaad.2018.08.055 . 1097-6787 . 30392755.
  18. Book: Clarke . Loren E. . Color Atlas of Differential Diagnosis in Dermatopathology . Clarke . Jennie T. . Helm . Klaus F. . 2014-03-01 . JP Medical Ltd . 978-93-5090-845-7 . 2020-12-06 . https://web.archive.org/web/20230111224601/https://books.google.com/books?id=CLeHAwAAQBAJ&q=Acral+lentiginous+melanoma++diagnosis&pg=PA310 . 2023-01-11 . live.
  19. Piliang . Melissa Peck . Acral Lentiginous Melanoma . Surgical Pathology Clinics . September 2009 . 2 . 3 . 535–541 . 10.1016/j.path.2009.08.005 . 26838538 .
  20. Book: Mooi . Walter . Pathology of Melanocytic Disorders 2ed . Krausz . Thomas . 2007-09-28 . CRC Press . 978-1-4441-1380-8 . 2020-12-06 . https://web.archive.org/web/20230111224601/https://books.google.com/books?id=mbrMBQAAQBAJ&q=Acral+lentiginous+melanoma++histology&pg=PA295 . 2023-01-11 . live.
  21. Scolyer . Richard A. . Long . Georgina V. . Thompson . John F. . Evolving concepts in melanoma classification and their relevance to multidisciplinary melanoma patient care . Molecular Oncology . April 2011 . 5 . 2 . 124–136 . 10.1016/j.molonc.2011.03.002 . 21482206 . 5528281 .
  22. Maverakis . E . Cornelius . L . Bowen . G . Phan . T . Patel . F . Fitzmaurice . S . He . Y . Burrall . B . Duong . C . Kloxin . A . Sultani . H . Wilken . R . Martinez . S . Patel . F . Metastatic Melanoma – A Review of Current and Future Treatment Options . Acta Dermato Venereologica . 2015 . 95 . 5 . 516–524 . 10.2340/00015555-2035 . 25520039 . free .
  23. Hardie . Claire M. . Wade . Ryckie G. . Wormald . Justin C. R. . Stafford . Brian . Elliott . Faye . Newton-Bishop . Julia . Dewar . Donald . Surgical excision methods for skin cancer involving the nail unit: A systematic review . Cochrane Evidence Synthesis and Methods . October 2023 . 1 . 8 . 10.1002/cesm.12026 . free .
  24. Morton . Donald L. . Thompson . John F. . Cochran . Alistair J. . Mozzillo . Nicola . Nieweg . Omgo E. . Roses . Daniel F. . Hoekstra . Harold J. . Karakousis . Constantine P. . Puleo . Christopher A. . Coventry . Brendon J. . Kashani-Sabet . Mohammed . Smithers . B. Mark . Paul . Eberhard . Kraybill . William G. . McKinnon . J. Gregory . 2014-02-13 . Final trial report of sentinel-node biopsy versus nodal observation in melanoma . The New England Journal of Medicine . 370 . 7 . 599–609 . 10.1056/NEJMoa1310460 . 1533-4406 . 4058881 . 24521106.
  25. Wei . Xiaoting . Wu . Di . Li . Hang . Zhang . Rui . Chen . Yu . Yao . Hong . Chi . Zhihong . Sheng . Xinan . Cui . Chuanliang . Bai . Xue . Qi . Zhonghui . Li . Ke . Lan . Shijie . Chen . Lizhu . Guo . Rui . September 2020 . The Clinicopathological and Survival Profiles Comparison Across Primary Sites in Acral Melanoma . Annals of Surgical Oncology . 27 . 9 . 3478–3485 . 10.1245/s10434-020-08418-5 . 1534-4681 . 7410855 . 32253677.
  26. Bradford . Porcia T. . Goldstein . Alisa M. . McMaster . Mary L. . Tucker . Margaret A. . Acral Lentiginous Melanoma: Incidence and Survival Patterns in the United States, 1986-2005 . Archives of Dermatology . April 2009 . 145 . 4 . 427–434 . 10.1001/archdermatol.2008.609 . 2735055 . 19380664 .
  27. Lino-Silva . Leonardo S. . Zepeda-Najar . César . Salcedo-Hernández . Rosa A. . Martínez-Said . Héctor . 2019 . Acral Lentiginous Melanoma: Survival Analysis of 715 Cases . Journal of Cutaneous Medicine and Surgery . 23 . 1 . 38–43 . 10.1177/1203475418800943 . 1615-7109 . 30221995.
  28. Web site: 2016-02-06 . Bob Marley Shouldn't Have Died from Melanoma . live . https://web.archive.org/web/20190727030546/https://www.skincancer.org/news/melanoma/marley . 2019-07-27 . 2016-10-11 . Skin Cancer Foundation.

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