Dermatoscopy of Neoplastic Skin Lesions: Recent Advances, Updates, and Revisions

Abstract

Dermatoscopy (dermoscopy) improves the diagnosis of benign and malignant cutaneous neoplasms in comparison with examination with the unaided eye and should be used routinely for all pigmented and non-pigmented cutaneous neoplasms. It is especially useful for the early stage of melanoma when melanoma-specific criteria are invisible to the unaided eye. Preselection by the unaided eye is therefore not recommended. The increased availability of polarized dermatoscopes, and the extended use of dermatoscopy in non-pigmented lesions led to the discovery of new criteria, and we recommend that lesions should be examined with polarized and non-polarized dermatoscopy. The "chaos and clues algorithm" is a good starting point for beginners because it is easy to use, accurate, and it works for all types of pigmented lesions not only for those melanocytic. Physicians, who use dermatoscopy routinely, should be aware of new clues for acral melanomas, nail matrix melanomas, melanoma in situ, and nodular melanoma. Dermatoscopy should also be used to distinguish between different subtypes of basal cell carcinoma and to discriminate highly from poorly differentiated squamous cell carcinomas to optimize therapy and management of non-melanoma skin cancer. One of the most exciting areas of research is the use of dermatoscopic images for machine learning and automated diagnosis. Convolutional neural networks trained with dermatoscopic images are able to diagnose pigmented lesions with the same accuracy as human experts. We humans should not be afraid of this new and exciting development because it will most likely lead to a peaceful and fruitful coexistence of human experts and decision support systems.

Keywords: Actinic keratosis; Basal cell carcinoma; Dermatoscopy; Dermoscopy; Melanoma; Squamous cell carcinoma.

Fig. 1

Chaos and clues in melanoma. a Asymmetry of structure and color (“chaos”); clues to malignancy: eccentric structureless zone, gray dots, on the left side, black dots in the periphery, thick reticular lines. Histopathologic diagnosis: melanoma. b Asymmetry of structure and color (“chaos”); clues to malignancy: eccentric gray and blue structureless zone, black dots in the periphery, segmental radial lines at the periphery, white lines. Histopathologic diagnosis: melanoma. Images courtesy of the Vienna Dermatologic Imaging Research Group, Department of Dermatology, Medical University of Vienna, Austria.

Fig. 2

Prominent skin markings and angulated lines in melanoma in situ. a Dermatoscopic image of a melanoma in situ on the thigh of a 68-year-old man. b In detail, lesion (a) shows prominent skin markings (linear intersecting furrows) as a clue to melanoma in situ. c Angulated lines and eccentric irregular hyperpigmented area as clues to melanoma in situ. Images courtesy of the Vienna Dermatologic Imaging Research Group, Department of Dermatology, Medical University of Vienna, Austria.

Fig. 3

Acral melanoma. Dermatoscopic image of an acral melanoma with asymmetry of structures (+ 1 point), asymmetry of color (+ 1 point), irregular blotch (+ 1 point), and the parallel furrows pattern (− 1 point) resulting in a BRAAFF-Score of 2 points. Despite absence of the parallel ridge pattern, it can be diagnosed as melanoma. Image courtesy of the Vienna Dermatologic Imaging Research Group, Department of Dermatology, Medical University of Vienna, Austria.

Fig. 4

Pigmented actinic keratosis. Lesions (a) and (b) show surface scaling and follicular openings. Additionally, characteristic rosettes (4 dots arranged in square) can dermatoscopically be seen in (b). The presence of angulated lines in both lesions are in line with the diagnosis of pigmented actinic keratosis. Images courtesy of the Vienna Dermatologic Imaging Research Group, Department of Dermatology, Medical University of Vienna, Austria.

Fig. 5

Acral lentiginous melanoma in situ of a 37-year-old woman. Dermatoscopy shows longitudinal lines of irregular thickness, spacing, and coloration. Note that the pigmentation involves less than $\raisebox{1ex}{$1$}\!\left/ \!\raisebox{-1ex}{$3$}\right.$ of the nail plate, demonstrating that size is not a good criterion for early lesions. Image courtesy of the Vienna Dermatologic Imaging Research Group, Department of Dermatology, Medical University of Vienna, Austria.

Fig. 6

Hypopigmented nodule on the back of a 72-year-old man viewed with the unaided eye. a Dermatoscopic examination of lesion (b) shows ulceration with serum crusts and adherent fibers. Central gray color surrounded by white lines and coiled vessels allows the differential diagnosis of an amelanotic melanoma. Histopathologic diagnosis: nodular melanoma (Clark level, IV; Breslow depth, 2.4 mm; ulceration, stage T3b). Images courtesy of the Vienna Dermatologic Imaging Research Group, Department of Dermatology, Medical University of Vienna, Austria.

Fig. 7

Lesion (a) shows the typical features of an infiltrative BCC such as branched vessels and small blue clods. The superficial BCC in (b) is typified by white lines. Images courtesy of the Vienna Dermatologic Imaging Research Group, Department of Dermatology, Medical University of Vienna, Austria.

Fig. 8

Highly differentiated SCC, in a 72-year-old man. Dermoscopy shows keratin with blood spots in the center and white circles in the periphery. Image courtesy of the Vienna Dermatologic Imaging Research Group, Department of Dermatology, Medical University of Vienna, Austria.