Ashfaq Marghoob, MD: Identifying Dermoscopic Patterns in Facial, Palmoplantar, Nail, and Mucosal Lesions

In this Q&A with Dermatology Times, Ashfaq A. Marghoob, MD, attending physician at Memorial Sloan Kettering Cancer Center, offers insights into dermoscopic techniques for evaluating unique anatomical areas often associated with diagnostic challenges.

Based on his presentations at the 2024 Elevate-Derm West Conference, Marghoob delves into specialized approaches for assessing lesions on the face, palms and soles, nails, and mucous membranes.

From identifying distinctive folliculocentric patterns in facial lesions to differentiating ridge-based pigmentation patterns in palmoplantar nevi, Marghoob aims to equip clinicians and advanced practice providers with key markers for discerning between benign and malignant findings in these complex regions.

Ashfaq Marghoob, MD | Image Credit: © Memorial Sloan Kettering Cancer Center

Q&A

Dermatology Times: What are some of the unique dermoscopic patterns or features that practitioners should be aware of when examining lesions on the face?

Marghoob: Facial skin has a different micro-anatomy compared to other non-glabrous skin in that it has an attenuated rete ridge pattern and has a high density of follicular openings. Furthermore, the melanocytic stem cell, from which lentigo maligna (LM) likely originates, is located in the hair bulge. This explains why many of the diagnostic features for LM are folliculocentric including the presence of asymmetric follicular openings, granularity around hair follicles (gray color), circle-within-circle sign, and perifollicular linear projections. When the malignant cells start to grow in the inter-follicular space then one can see angulated lines, rhomboidal structures, and blotches. This differs from what is seen in a solar lentigo on the face, which consists of a lesion with moth eaten borders, fingerprinting and symmetric pigment around follicular openings.

Dermatology Times: What specific patterns or findings should dermatologists look for in the palm and sole regions?

Marghoob: To differentiate nevi from melanoma on palms/soles requires correctly identifying the ridges and furrows of the dermatoglyphics. In nevi, the pigment is confined to the invaginations of the dermatoglyphics, creating a parallel furrow pattern. In melanoma, the pigment is concentrated on the ridges creating the parallel ridge pattern. In addition, pigment patches involving both the ridges and furrows creating multi-shades of brown pigmented blotches …this is also a feature suggestive of melanoma.

Dermatology Times: What are the key dermoscopic features that can help differentiate between benign and malignant nail lesions?

Marghoob: There are a few clinical features that trump any dermoscopic features for melanoma and they include a triangular shape to the melanonychia striata, involvement of greater than half of the nail plate, presence of associated nail dystrophy, and the presence of Hutchinson’s sign. In the absence of these features, the dermoscopy of the nail band can help differentiate pigmented lesions from melanoma. In a melanocytic activation process (increased melanin production but no increase in melanocyte proliferation) as seen in ethnic pigmentation the pigment has a gray to tan color and the nail band lacks prominent striations within it. Melanocytic proliferation leads to nevi or melanoma. In nevi, the band is composed of individual striations (lines) that are distributed in an symmetric manner and the lines preserve their parallelism. In melanoma the individual lines in the band are distributed in an asymmetric manner and the lines often lose their parallelism. The main point regarding nails is to remember that there are clinical features that trump dermoscopic features.

Dermatology Times: Could you share some dermoscopic signs that may be indicative of concerning lesions in mucosal areas?

Marghoob: Benign mucosal lesion tend to only display one pattern consisting of lines, circles, half circles or globules. Melanoma often will display a multi-component pattern. However, the most sensitive dermoscopic feature for melanoma on mucosal surfaces is not structures but rather colors. The presence of blue, gray, or white color has a sensitivity for melanoma of 100% and a specificity of 64%.

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