Benign lesions in skin of color
|Description||This chapter describes the dermoscopy of various benign lesion in skin of color such as dermatofibroma, angioma, seborrheic keratoses and sebaceous hyperplasia|
|Responsible author||Richard Usatine → send e-mail|
|Status update||July 19, 2023|
|Status by||Ralph P. Braun|
Skin of color, Benign lesions, Angioma, Dermatofibroma, Soc, Sebaceous hyperplasia, Seborrheic keratoses 06-Benign lesions in skin of color – cite! 06-Benign lesions in skin of color (message) 06-Benign lesions in skin of color – participate!
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. 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. 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.
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. 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.
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. 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. These are graphical representations of the aforementioned trends in nevus morphology.
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.
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) 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. 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. 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). 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. Acral pigmented lesions were more commonly seen in those with Fitzpatrick skin types IV to VI compared to skin types I to II. 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. 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:
A dermatofibroma is a scar-like benign tumor that is firm to palpation and often shows a dimple sign. On dermoscopy it typically shows a central hypopigmented or pink scar-like area surrounded by fine reticular network.
- Delicate pigment (reticulated) network at the periphery of the lesion.
- A central scar-like white or pink patch with or without shiny white lines
Additional dermoscopic features:
- Ring-like globules
- White network -white lines surrounding small islands of brown pigment or surrounding globule-like (i.e., “ring-like”) structures.
- Homogenous areas with brown color
- Vascular structures
- Rarely comedo-like openings, scale, ulceration, peripheral collarette fissures, ridges and mammillated surface.
The best description of DF in skin of color was performed in Morocco from 2015 to 2016 and included 100 cases.  All the patients had a dark skin phototype (Fitzpatrick scale types IV and V). A total of 14 morphological dermoscopic structures were distinguished, and 17 dermoscopic patterns were observed, with the most common pattern being the central white patch and peripheral pigment network (21%).
Examples in a variety of patients with skin of color
Central shiny white structures that are creating polygonal patterns (not one of typical 10 patterns described by Zaballos et al.)
Never forget to do the pinch test:
Angioma and other vascular lesions
Angiomas are benign vascular tumors that have the dermoscopic features of lacunae and septae. These features are found independent of the color of the skin. Angiomas can have colors that vary from a light pink to a deep purple regardless of the skin type. Whether angiomas are more likely to be lighter pinks in light-skinned persons and darker reds and purples in dark skinned persons is possible but not proven.
- Dark lacunae: sharply demarcated, ovoid structures with a dark blue, dark violaceous or black color.
- Blue-White veil: confluent blue pigmentation with an overlying whitish haze.
- Ulceration and surface scale may be present.
- Rarely, a rainbow pattern may be present.
Pyogenic granuloma (PG) is a relatively common benign acquired friable vascular growth of the skin and mucous membranes often started by trauma. PG is a misnomer as it is neither pyogenic nor granulomatous. However, it often has a purulent-appearing exudate that explains how it got its name. A more accurate name in use is “lobular capillary hemangioma”.
- Reddish or red-whitish homogeneous area: a structureless zone whose color varies from completely red to red with whitish zones.
- White collarette: a ring-shaped or arcuate squamous structure that is usually located at the periphery of the lesions.
- White rail lines: white streaks that intersect the lesion.
- Vascular structures (dotted vessels, hairpin vessels, linear-irregular vessels, telangiectasias, polymorphous vessels).
- Ulceration may be present
The most frequent dermoscopic pattern of PG consists of reddish homogenous areas separated by white lines resembling rails and surrounded by a white collarette. Dermoscopy of pyogenic granulomas are not known to vary by skin type.
Low-grade malignant vascular tumor caused by human herpesvirus-8 (HHV-8) producing a vascular proliferation.
- Homogeneous pattern with differing colors (i.e., whitish, pinkish, reddish, bluish, or violaceous) in different lesions in the same patient.
- Rainbow-like appearance: multicolored areas showing various colors of the rainbow spectrum.
- Whitish structureless areas, vascular structures, scale, and a white collarette may also be seen.
Malformation involving lymphatic vessels that may be present at birth or occur later typically from trauma (including postsurgical). The clinical appearance has been described as looking like frog spawn. There is no known variation based on skin color.
Note how this resembles the hyphema that might be seen in an eye that has experienced trauma in which there is bleeding in the anterior chamber:
This has been incorrectly compared to hypopyon which consists of white blood cells that create a white layer at the bottom of the anterior chamber in iritis: 
Courtesy of the Color Atlas and Synopsis of Family Medicine. Usatine R, Smith M, Mayeaux EJ, Chumley H. The Color Atlas and Synopsis of Family Medicine, 3rd Edition. McGraw-Hill, New York, 2018.
I suggest it is time to rename the sign the “hyphema sign”.
- 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.
- 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.
- 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.
- Zalaudek et al.: Nevus type in dermoscopy is related to skin type in white persons. Arch Dermatol 2007;143:351-6. PMID: 17372099. DOI.
- Tan & Stein: Dermoscopic patterns of acral melanocytic lesions in skin of color. Cutis 2019;103:274-276. PMID: 31233579.
- 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.
- Zaballos et al.: Dermoscopy of dermatofibromas: a prospective morphological study of 412 cases. Arch Dermatol 2008;144:75-83. PMID: 18209171. DOI.
- Ferrari et al.: Typical and atypical dermoscopic presentations of dermatofibroma. J Eur Acad Dermatol Venereol 2013;27:1375-80. PMID: 23176079. DOI.
- Kelati et al.: Beyond classic dermoscopic patterns of dermatofibromas: a prospective research study. J Med Case Rep 2017;11:266. PMID: 28927449. DOI.
- Zaballos et al.: Dermoscopy of solitary angiokeratomas: a morphological study. Arch Dermatol 2007;143:318-25. PMID: 17372096. DOI.
- Zaballos et al.: Dermoscopy of pyogenic granuloma: a morphological study. Br. J. Dermatol. 2010;163:1229-37. PMID: 20846306. DOI.
- Cheng et al.: Rainbow pattern in Kaposi's sarcoma under polarized dermoscopy: a dermoscopic pathological study. Br. J. Dermatol. 2009;160:801-9. PMID: 19067686. DOI.
- Vázquez-López et al.: Dermoscopic rainbow pattern in non-Kaposi sarcoma lesions. Br. J. Dermatol. 2009;161:474-5. PMID: 19438855. DOI.
- Gencoglan et al.: Hypopyon-like features: new dermoscopic criteria in the differential diagnosis of cutaneous lymphangioma circumscriptum and haemangiomas?. J Eur Acad Dermatol Venereol 2012;26:1023-5. PMID: 21645121. DOI.
Seborrheic keratoses are the most common benign epithelial lesion in adults. Their dermoscopic features have been well described in the chapter above. The following schematic shows the most typical features.
Schematic of SK
Seborrheic keratoses are found with shades of colors that span light brown to dark brown. They can also have multiple shades of brown and areas of white within a single benign lesion. The darkest SKs can mimic melanoma clinically which makes the understanding of the dermoscopic features so important. 
There is no data on how SKs in darker skin compare to SKs in lighter skin, but many have observed that dark SKs are common in dark skin.
Examples of darker SKs in persons with skin of color
Sebaceous hyperplasia represents enlarged sebaceous glands principally found on the forehead, cheeks and nose in older adults. They can be found in persons of all skin colors and are typically 2 to 5 mm in diameter with a yellowish-white color and a light brown central opening. Due to some prominent vessels they may be mistaken for a basal cell carcinoma. Fortunately, dermoscopy almost always allows us to distinguish them from a BCC.
Dermoscopic features of sebaceous hyperplasia in all skin types include:
- White to yellowish-white globules that resemble popcorn in appearance. When the color is more yellow think of them as buttered popcorn (the butter is the sebum).
- Crown vessels are fine branching vessels that are more prominent on the periphery and do not cross the midline.
- Light brown central umbilication of the pilosebaceous unit. It has been described having the appearance of a round Bonbon caramel toffee.
Links to additional chapters on Skin of Color
- Papageorgiou et al.: The limitations of dermoscopy: false-positive and false-negative tumours. J Eur Acad Dermatol Venereol 2018;32:879-888. PMID: 29314288. DOI.
- Sahin et al.: A comparison of dermoscopic features among lentigo senilis/initial seborrheic keratosis, seborrheic keratosis, lentigo maligna and lentigo maligna melanoma on the face. J Dermatol 2004;31:884-9. PMID: 15729860. DOI.
- Mansur & Yildiz: A diagnostic challenge: inflamed and pigmented seborrheic keratosis. Clinical, dermoscopic, and histopathological correlation. Dermatol Online J 2019;25:. PMID: 30982311.
- Salerni et al.: Seborrheic keratosis-like melanoma. J Am Acad Dermatol 2015;72:S53-5. PMID: 25500043. DOI.
- Braun et al.: Differential Diagnosis of Seborrheic Keratosis: Clinical and Dermoscopic Features. J Drugs Dermatol 2017;16:835-842. PMID: 28915278.
- Carrera et al.: Dermoscopic Clues for Diagnosing Melanomas That Resemble Seborrheic Keratosis. JAMA Dermatol 2017;153:544-551. PMID: 28355453. DOI.
- Zaballos et al.: Dermoscopy of sebaceous hyperplasia. Arch Dermatol 2005;141:808. PMID: 15967945. DOI.
- Oztas et al.: Bonbon toffee sign: a new dermatoscopic feature for sebaceous hyperplasia. J Eur Acad Dermatol Venereol 2008;22:1200-2. PMID: 18540985. DOI.