Benign melanocytic nevi in skin of color
The following 4 studies describe how skin type impacts the structure and color of melanocytic nevi:
1. Tuma et al. performed the first study that compared the dermoscopic differences in acquired melanocytic nevi between skin types V/VI to that of skin types I/II.[1] They concluded that dermoscopy of the acquired melanocytic nevi in skin type V/VI showed a reticular pattern, brown color, and tendency toward central hyperpigmentation whereas the acquired nevi in skin type I/II showed a light-brown color and a tendency toward structureless pattern and multiple areas of hypopigmentation (figure 1). Also, nevi in skin type V/VI displayed a higher frequency of gray and black colors. Black color (as dots centrally, blotches, and pigmented network) was not seen in the light-skinned group but was found in almost 5% of the lesions in the dark-skinned individuals.
Figure 1. These images of acquired melanocytic nevi are adapted from Tuma et al. Note the nevus on lighter skin (left) demonstrates a light-brown color, structureless pattern, and multiple areas of hypopigmentation. The nevus on darker skin (right) demonstrates a reticular pattern, dark brown color, and central hyperpigmentation.
2. Lallas et al. analyzed 300 naevi from subjects with skin type V and VI and found significant differences in the naevus pattern between these two groups.[2] The majority of naevi in skin type V displayed a reticular pattern, whereas persons with skin type VI more frequently exhibited a structureless pattern. Skin type V individuals typically had dark brown colored nevi whereas skin type VI individuals were more likely to have black, blue and grey colors in their nevi.[2]
3. Fonseca et al. performed a cross-sectional analysis of the dermoscopic patterns and structures of melanocytic naevi on the back and legs of adolescents, including a minority of participants with skin of color.[3] Regarding nevi on the back, they found that Hispanic ethnicity, darker hair color and darker skin color were associated with a relatively higher percentage of reticular nevi and a lower percentage of homogenous nevi (compared to nevi on the backs of non-Hispanic whites, those with lighter hair color, and those with lighter skin color). On the legs, those with darker skin color had a higher percentage of reticular nevi and a lower percentage of homogenous nevi compared to those with lighter skin color.[3]
4. Zalaudek et al. used dermoscopy to study how nevus type is related to skin type in persons with skin types I to IV.4 While they did not include persons of skin types V and VI, they did look at intermediate skin types that can be found in persons of lighter skin of color.[4] They found these trends with darkening of skin type:
- Decreasing prevalence of light brown color
- Increasing prevalence of dark brown color
- Decreasing prevalence of central hypopigmentation
- Increasing prevalence of central hyperpigmentation
Need permission: The following graphs were adapted from Zalaudek et al.[4] These are graphical representations of the aforementioned trends in nevus morphology.
nevus on type II skin, with light brown color and central hypopigmentation
nevus on type V skin with dark brown color and central hyperpigmentation.
The following images are from the ISIC archive. Note the light brown color and central hypopigmentation of the nevus on type I skin and the dark brown color and central hyperpigmentation of the nevus on type V skin.
Nevus on type I skin – hypopigmented center
Nevus on type V skin – hyperpigmented center
INTRADERMAL NEVI
There has been no literature published regarding the dermoscopic features of intradermal nevi in patients of color. Below are representative images of intradermal nevi.
Note the appearance of the intradermal nevus on a patient of color (left) compared to the intradermal nevus on a patient with light skin color (right). The intradermal nevus on the patient of color has increased pigmentation.
ACRAL (VOLAR) MELANOCYTIC NEVI
The following is a compilation of literature published on acral nevi in skin of color patients:
1. Tan and Stein recognize the diagnostic challenges of acral lesions due to the unique nature of acral surfaces.[5] Dermoscopy assists in the differentiation of benign from malignant lesions, which is of particular importance on examination of skin of color patients, since acral lentiginous melanoma makes up a significant proportion of melanoma cases in this population.[5] Visualization of the parallel ridge pattern (parallel linear pigmentation along the ridges of the dermatoglyphics on volar surfaces) has high sensitivity and specificity for the diagnosis of acral lentiginous melanoma (86% and 99%, respectively).[5] Common features of benign, acquired acral nevi include parallel furrow, lattice-like, and fibrillar patterns.
2. Madankumar et al. studied acral melanocytic lesions in skin of color and white patients in the United States.[6] Acral pigmented lesions were more commonly seen in those with Fitzpatrick skin types IV to VI compared to skin types I to II.[6] The following were the most common dermoscopic patterns of acral nevi in skin-of-color patients:
- Parallel furrow (43%)
- Lattice-like pattern (13%)
- Homogenous pattern (10%)
In comparison, the most common patterns in non-Hispanic white patients were:
- Parallel furrow (48%)
- Lattice-like pattern (16%)
- Fibrillar pattern (8%)
3. Barquet et al. studied a diverse Latin American population in Uruguay.[7] The Uruguayan population is heterogeneous; most of the population is of European descent (mainly Spanish and Italian), but there are also people of indigenous (1---20%) and African (7---15%) descent. The following dermoscopic patterns were seen among 158 acral volar nevi in 80 patients:
- Parallel furrow pattern (51.3% of nevi)
- Lattice-like pattern (13.3%)
- Homogeneous pattern (12.7%)
- Globular pattern (9.5%)
- Fibrillar pattern (7%)
They concluded that no new dermoscopic patterns were observed in this population; the patterns described in Asian and European literature also apply to their population.7
Here are some examples of acral nevi:
2 examples of parallel furrow patterns in AA persons
Benign lattice pattern on palms of an AA person
A 1 cm hyperpigmented macule on the sole of a 30-year-old African-American man.
Note the fibrillar pattern. A biopsy was performed because of its size and rapid growth. It was determined to be a benign acral nevus
Links to additional chapters on Skin of Color
References
- ↑ Tuma et al.: Dermoscopy of black skin: A cross-sectional study of clinical and dermoscopic features of melanocytic lesions in individuals with type V/VI skin compared to those with type I/II skin. J Am Acad Dermatol 2015;73:114-9. PMID: 25982540. DOI.
- ↑ 2.0 2.1 Lallas et al.: Dermoscopic nevus patterns in skin of colour: a prospective, cross-sectional, morphological study in individuals with skin type V and VI. J Eur Acad Dermatol Venereol 2014;28:1469-74. PMID: 24237599. DOI.
- ↑ 3.0 3.1 Fonseca et al.: Cross-sectional analysis of the dermoscopic patterns and structures of melanocytic naevi on the back and legs of adolescents. Br. J. Dermatol. 2015;173:1486-93. PMID: 26189624. DOI.
- ↑ 4.0 4.1 Zalaudek et al.: Nevus type in dermoscopy is related to skin type in white persons. Arch Dermatol 2007;143:351-6. PMID: 17372099. DOI.
- ↑ 5.0 5.1 5.2 Tan & Stein: Dermoscopic patterns of acral melanocytic lesions in skin of color. Cutis 2019;103:274-276. PMID: 31233579.
- ↑ 6.0 6.1 Madankumar et al.: Acral melanocytic lesions in the United States: Prevalence, awareness, and dermoscopic patterns in skin-of-color and non-Hispanic white patients. J Am Acad Dermatol 2016;74:724-30.e1. PMID: 26803347. DOI.
- ↑ Barquet et al.: Dermoscopic patterns of 158 acral melanocytic nevi in a Latin American population. Actas Dermosifiliogr 2013;104:586-92. PMID: 23985085. DOI.
