Flat/Pale Brown/Multicolored
 FIGURE 9.1 Color wheel: flat/pale brown/multicolored. |
Step 1: Is the lesion flat or raised? Flat
Step 2: What color is the lesion on clinical assessment? Pale Brown
Step 3: What is the dermoscopic color? Multicolored
Step 4: Is further elucidation needed to decide whether to biopsy or not? Yes
Is this a malignant or benign pattern?
Take a look at the color wheel in Figure 9.1.
These lesions really expand our differential, but the majority of the time, pale brown, flat lesions are generally benign.
Our malignancies include malignant melanoma, pigmented basal cell carcinoma (BCC), and pigmented squamous cell carcinomas (SCCs).
Our benign lesions include lichen planus-like keratosis or ISK, dermatofibroma, and congenital/junctional nevi.
Benign Lesions
Pearls
Flat/Pale Brown/Multicolored
Clinically, these will have been present since childhood.
If these are a result of iatrogenic causes such as UV light or rubbing/irritation, this can result in multiple colors. You may see shades of brown and sometimes black.
They will resemble other lesions in the area. Patients will have their own “signature” lesion.
Step 4 Pattern Highlights: Review your patterns from Chapter 1!
Symmetrical reticular pattern with darker dots
Overall, symmetry, especially at the periphery
Bottom line: Benign, biopsy unnecessary.
Junctional/Combined Congenital Nevi
Examples
Figures 9.2, 9.3, 9.4 and 9.5 show a clinically flat, pale brown lesion (A, B) that is dermoscopically multicolored (brown + other = gray, pink, and/or yellow). Dermoscopically, we can see a symmetric reticular network pattern with dark dots of gray within the network. Often, these lesions will look similar to other nevi in the area—each patient may have his or her own “signature lesions!” Diagnosis: Junctional/combined congenital nevi.
Bottom line: benign, biopsy unnecessary.
Figures 9.4A-D and 9.5A, B are examples of a patient’s “signature lesions.” The patient’s lesions in Figure 9.4A-D all have a similar coloring and pattern with the dark dots of gray in the center of the network. The lesions from the patient in Figure 9.5A, B have a very different appearance but are similar to one another. The darker brown/gray pigment is scattered in a horseshoe-like distribution at the periphery of the lesions. Diagnosis: Junctional/combined congenital nevi.
Bottom line: Benign, biopsy unnecessary
 FIGURE 9.2 Clinically flat lesions that are pale brown, with a multicolored (brown + other = gray, pink, and/or yellow) dermoscopic pattern. Review these clinical and dermoscopic examples of a junctional nevi/congenital nevus. A,B: Clinical examples. C: The dermoscopic example shows a symmetric reticular network pattern with dark dots on the network. These lesions often resemble other nevi—signature nevi. |
 FIGURE 9.3 Clinically flat lesions that are pale brown, with a multicolored (brown + other = gray, pink, and/or yellow) dermoscopic pattern. Review these clinical and dermoscopic examples of a junctional nevi/congenital nevus. A,B: Clinical examples. C: The dermoscopic example shows a symmetric reticular network pattern with dark dots on the network. These lesions often resemble other nevi—signature nevi. |
 FIGURE 9.4 A-D: Multiple congenital nevi that resemble each other. These are examples of a patient’s “signature lesions,” that is, lesions that resemble each other. A-C: Clinically flat lesions that are pale brown, with a multicolored (brown + other = gray, pink, and/or yellow) dermoscopic pattern. Review these clinical and dermoscopic examples of a junctional nevi/congenital nevus. A,B: Clinical examples. C: The dermoscopic example shows a symmetric reticular network pattern with dark dots on the network. This lesion often resembles other nevi—signature nevi. D-F: Clinically flat lesions that are pale brown, with a multicolored (brown + other = gray, pink, and/or yellow) dermoscopic pattern. Review these clinical and dermoscopic examples of a junctional nevi/congenital nevus. D,E: Clinical examples. F: The dermoscopic example shows a symmetric reticular network pattern with dark dots on the network. This lesion often resembles other nevi—signature nevi. |
 FIGURE 9.4 (Continued) G-I: Clinically flat lesions that are pale brown, with a multicolored (brown + other = gray, pink, and/or yellow) dermoscopic pattern. Review these clinical and dermoscopic examples of a junctional nevi/congenital nevus. G,H: Clinical examples. I: The dermoscopic example shows a symmetric reticular network pattern with dark dots on the network. This lesion often resembles other nevi—signature nevi. J-L: Clinically flat lesions that are pale brown, with a multicolored (brown + other = gray, pink, and/or yellow) dermoscopic pattern. Review these clinical and dermoscopic examples of a junctional nevi/congenital nevus. J,K: Clinical examples. L: The dermoscopic example shows a symmetric reticular network pattern with dark dots on the network. This lesion often resembles other nevi—signature nevi. |
 FIGURE 9.5 Clinically flat lesions that are pale brown, with a multicolored (brown + other = gray, pink, and/or yellow) dermoscopic pattern. Review these clinical and dermoscopic examples of a junctional nevi/congenital nevus. A,B: Clinical examples. C: The dermoscopic example shows a symmetric reticular network pattern with dark dots on the network. This lesion often resembles other nevi—signature nevi. D-F: Clinically flat lesions that are pale brown, with a multicolored (brown + other = gray, pink, and/or yellow) dermoscopic pattern. Review these clinical and dermoscopic examples of a junctional nevi/congenital nevus. D,E: Clinical examples. F: The dermoscopic example shows a symmetric reticular network pattern with dark dots on the network. This lesion often resembles other nevi—signature nevi. |
Lichen Planus-Like Keratosis or Benign Lichenoid
Pearls
Flat/Pale Brown/Multicolored
There are two possibilities for the origin of these lesions:
A solar lentigo undergoing regression or an inflammatory reaction
A seborrheic keratosis undergoing regression or an inflammatory reaction
When trying to distinguish between melanomas, it is useful to note the following:
LPLKs have more substance on palpation than superficial spreading MMs.
Pale brown, clinically flat lesions are usually benign.
LPLKs will typically show up on skin types 2 and 3.
LPLKs will generally resemble other lesions on the patient.
Step 4 Pattern Highlights: Review your patterns from Chapter 1!
The inflammation leads to a nonspecific vascular pattern.
Often, you will see clumps of dark pigment around benign structures:
Diffusely on a background of hypomelanosis
Localized in small clusters
Look for clues of benign features: ridges, sharp borders, moth-eaten borders, fingerprint patterns, milia-like cysts, and comedo-like openings.
These are often the most difficult lesions to differentiate from malignant melanoma and nonmelanoma skin cancers, so we will biopsy these lesions often!
Examples
Figure 9.6 is a clinically flat, pale brown lesion (Figure 9.6A, B) with a dermoscopically multicolored (brown + other = gray, pink, or yellow) pattern (Figure 9.6C). We can see diffuse granularity within the lesion dermoscopically, which can be difficult to distinguish from melanoma,
but note the moth-eaten border that is characteristic of a benign lentigo undergoing regression. Diagnosis: Lichen planus-like keratosis or benign lichenoid.
but note the moth-eaten border that is characteristic of a benign lentigo undergoing regression. Diagnosis: Lichen planus-like keratosis or benign lichenoid.
 FIGURE 9.6 Clinically flat lesions that are pale brown, with a multicolored (brown + other = gray, pink, and/or yellow) dermoscopic pattern. Review these clinical and dermoscopic examples of benign lichen planus-like keratosis. A,B: Clinical examples. C: The dermoscopic example shows the diffuse granularity that can be difficult to distinguish from melanoma. Note the moth-eaten border, seen in benign lentigo. |
Bottom line: Use caution; biopsy is recommended.
Figure 9.7 is a clinically flat, pale brown lesions (Figure 9.7A, B) with a dermoscopically multicolored (brown + other = gray, pink, or yellow) pattern (Figure 9.7C). We can see diffuse granularity and nonspecific inflammation within the lesion dermoscopically, which can be difficult to distinguish from melanoma, but note the moth-eaten border that is characteristic of a benign or irritated seborrheic keratosis. Diagnosis: Lichen planus-like keratosis or benign lichenoid.
Bottom line: Use caution; biopsy is recommended.
Figure 9.8 is a clinically flat, pale brown lesion (Figure 9.8A, B) with a dermoscopically multicolored (brown + other = gray, pink, or yellow) pattern (Figure 9.8C). We can see localized granularity within the lesion dermoscopically, again making it difficult to distinguish from melanoma, but note the clear ridges and moth-eaten border that are characteristic of a benign lentigo or irritated seborrheic keratosis. Diagnosis: Lichen planus-like keratosis or benign lichenoid.
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