Tender growth on toe

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Tender growth on toe

J Fam Pract. 2008 July;57(7):473-475

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References

1. Freedberg I. Acral lentiginous melanoma. In: Fitzpatrick’s Dermatology in General Medicine. 5th ed. New York: McGraw-Hill; 1999;767:1081-1083.

2. Stalkup JR, Orengo IF, Katta R. Controversies in acral lentiginous melanoma. Dermatol Surg. 2002;28:1051-1059.

3. Swetter SM. Malignant melanoma. Available at: http://www.emedicine.com/DERM/topic257.htm. Accessed June 6, 2008.

4. Cress RD, Holly EA. Incidence of cutaneous melanoma among non-Hispanic whites, Hispanics, Asians, and blacks: an analysis of California cancer registry data, 1988-93. Cancer Causes Control. 1997;8:246-252.

5. Saldanha G, Potter L, Daforno P, Pringle JH. Cutaneous melanoma subtypes show different BRAF and NRAS mutation frequencies. Clin Cancer Res. 2006;12:4499-4505.

6. Green A, McCredie M, MacKie R, et al. A casecontrol study of melanomas of the soles and palms (Australia and Scotland). Cancer Causes Control. 1999;10:21-25.

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9. Rosen T. Acral lentiginous melanoma misdiagnosed as verruca plantaris: a case report. Dermatology Online Journal. 2006;12(4):3.-Available at: http://dermatology.cdlib.org/124/case_reports/melanoma/rosen.html. Accessed June 6, 2008.

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Diagnosis: Acral lentiginous melanoma

A wedge biopsy of the lesion showed that the patient had acral lentiginous melanoma. ALM is a less common subtype of melanoma. (The other subtypes are superficial spreading malignant melanoma, nodular melanoma, and lentigo maligna melanoma.) Acral refers to its typical location, occurring in the distal extremities. The term lentiginous refers to its characteristic histopathologic finding.^1,2 Unlike the other subtypes of melanoma, ALM typically affects all ethnic groups. In non-white populations it constitutes 29% to 72% of all melanomas.³ In Caucasian patients it accounts for 2% to 8% of all melanomas.

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In non-white populations, acral lentiginous melanoma constitutes 29% to 72% of all melanomas

In many cases, ALM presents with the typical “ABCD” features of melanoma. These include asymmetry, border irregularity, color variegation, and a diameter greater than 6 mm. Lesions on the palmo-plantar surface may be macular, papular, or nodular, and may ulcerate. ALM may involve the nail as well.

As in our case, however, not all cases are typical. Amelanotic lesions may mimic a variety of skin conditions and pose a diagnostic challenge.

ALM is not linked to sun exposure

The pathogenesis of ALM is unclear. Unlike the other types of melanoma, in which sun exposure is clearly identified as an etiologic factor, ALM has not been definitively linked to exposure. In fact, ALM occurs in patients with more darkly pigmented skin, a group not typically considered at risk for melanoma. In African American patients, Hispanic patients, and Asian patients, ALM is the most common subtype of melanoma.⁴

BRAF/NRAS mutations seem to play an important role in all the major subtypes of cutaneous melanoma.⁵ Recent studies indicate that nevoid precursor lesions, high total body nevus count, and plantar nevi act as predisposing lesions to ALM.^2,6

Injury to the hands and feet. Another common association with ALM is penetrative injury of the hands and feet. There is no clinical or research-based evidence to support this association and therefore the role of trauma in the pathogenesis of ALM is controversial. This association may be seen in some cases because acral sites are more prone to trauma than the rest of the body.⁷

Tender growth on toe

References

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