SHORT COMMUNICATION

Magnified Dermoscopy Allows Better Differentiation between Dermal Nevi and Basal Cell Carcinoma

Joanna POGORZELSKA-DYRBUŚ^1*, Maria Teresa FERNÁNDEZ-FIGUERAS² and Jacek C. SZEPIETOWSKI^3,4

¹“Estevita” Specialist Medical Practice, Tychy, Poland, ²Pathology Department, Hospital Universitari General de Catalunya, Barcelona, Spain, ³Department of Dermato-Venereology, 4th Military Hospital, Wroclaw, Poland, and ⁴Division of Dermatology, Venereology and Clinical Immunology, Faculty of Medicine, Wroclaw University of Science and Technology, Wroclaw, Poland. ^*Email: jpogorzelskadyrbus@gmail.com

 

 

Dermal nevi (DN) and basal cell carcinoma (BCC) are among the most common nodular lesions on the face sometimes presenting with similar dermoscopic features (1). Magnified dermoscopy (MD), thanks to magnification of up to 400x, can improve diagnostic accuracy of various lesions. So far, the literature on MD remains scarce, but the first observation published to date has shown that MD can reveal significant differences between DN and BCC (2). The purpose of our study was to find the characteristic MD features of both DN and BCC that could enable their better differential diagnosis.

METHODS

A retrospective analysis of dermoscopic images from 73 histopathologically confirmed facial lesions (DN and BCC) was performed in standard dermoscopy (SD) (20x magnification) and MD (400x). All images were acquired using the Medicam 1000 (FotoFinder Systems, Bad Birnbach, Germany), and MD examination was performed with the D Scope III lens (FotoFinder Systems). Imaging data were jointly evaluated by two reviewers (JPD and JS) unaware of the results of histopathological examination. Image interpretation was performed in a consensus-based manner. Fifty-one (69.9%) of lesions were diagnosed as BCC and twenty-two (30.1%) as DN. Among SD features, morphology of the vessels and presence of pigmentation were evaluated, for MD, roundish and polygonal structures, structures with fading borders, granules and vessels according to the terminology criteria were analysed (3).

Patient characteristics and dermoscopic features were compared between DN and BCC. Categorical variables were compared using the χ² test or Fisher exact test depending on the number of analysed variables, while continuous variables were compared using the Mann–Whitney U test due to their non-normal distribution, after evaluation of normality in the Shapiro–Wilk test. The diagnostic utility of individual dermoscopic features, including sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV), for differentiation between DN vs BCC was also calculated. The threshold for statistical significance was predetermined at a 2-sided alpha of <0.05. All statistical analyses were performed using Statistica version 13.0 (StatSoft Inc., Tulsa, OK, USA).

RESULTS

The SD and MD features of both types of lesions are presented in Table I, and examples of features in both types of imaging in both BCC and DN are presented in Fig. 1. Among MD features, the roundish structures were observed in 90.9 % of DN and in none of the BCCs (p<0.001). Polygonal structures were present in 6 (27.2%) of DN and in 1 (1.9%) of BCC (p=0.002). MD allowed to observe vessels invisible in SD, with a statistically significantly higher prevalence of arborizing, irregular and looped vessels in BCC cases. Roundish structures observed in MD demonstrated the highest diagnostic performance, with very high sensitivity (91.0%) and perfect specificity (100%) for DN, as presented in Table II. Coma vessels in SD also showed strong discriminatory potential, with 77.0% sensitivity and 94.0% specificity. In contrast, the presence of arborizing or irregular vessels in MD strongly favoured the diagnosis of BCC, with specificity of both at respectively 80.0% and 76.0% for differentiation vs DN.

Table I. Dermoscopy and patient characteristics of the analyzed cohort

Variable	DN, n (%)	BCC, n (%)	p-value
Age	42.0 [34.5–58.5]	69.0 [56.5–76.0]	<0.001
Female gender	17 (77.3%)	40 (78.4%)	0.78
Localization			0.001
Cheek	9 (40.9%)	21 (41.2%)
Chin	6 (27.3%)	17 (33.3%)
Nose	5 (22.7%)	11 (21.6%)
Forehead	2 (9.1%)	2 (3.9%)
Roundish structures in MD	20 (90.9%)	0 (0.0%)	<0.001
Structures with fading borders in MD	14 (63.6%)	23 (45.1%)	0.146
Polygonal structures in MD	6 (27.2%)	1 (1.9%)	0.002
Granules in MD	10 (45.5%)	18 (35.3%)	0.413
Looped vessels in MD	9 (40.9%)	38 (74.5%)	0.006
Arborizing vessels in MD	1 (4.5%)	41 (80.4%)	<0.001
Irregular vessels in MD	1 (4.5%)	39 (76.5%)	<0.001
Linear vessels in MD	10 (45.5%)	31 (60.8%)	0.226
Linear vessels in SD	16 (72.7%)	40 (78.4%)	0.597
Tree-like vessels in SD	4 (18.2%)	34 (66.7%)	<0.001
Coma vessels in SD	17 (77.3%)	3 (5.8%)	<0.001
Pigment in SD	16 (72.7%)	14 (27.5%)	<0.001
BCC: basal cell carcinoma; DN: dermal nevus; MD: magnified dermoscopy; SD: standard dermoscopy.

Fig. 1. Dermoscopic and magnified dermoscopic features of dermal nevi and basal cell carcinoma. DN in standard magnification (A) and in MD (B-D). Brown roundish structures with a darker rim corresponding to melanocytes (black arrows). Structures with fading borders corresponding to melanophages indicated by red arrows, and granule corresponding to free melanin (yellow arrow). Polygonal structures corresponding to pigmented keratinocytes (asterisk). BCC in standard magnification (E), and in MD (F-I). Structures with fading borders (red arrow) and looped vessel (black arrow) (F). Looped vessels (G), irregular (H), and arborizing (I) indicated by black arrows

Table II. Diagnostic performance of dermoscopic features in differentiating dermal nevi from basal cell carcinoma

Feature	Sensitivity	Specificity	PPV	NPV
Roundish structures in MD	0.91	1	1	0.96
Structures with fading borders in MD	0.64	0.55	0.38	0.78
Polygonal structures in MD	0.27	0.98	0.86	0.76
Granules in MD	0.45	0.65	0.36	0.73
Looped vessels in MD	0.41	0.26	0.19	0.5
Arborizing vessels in MD	0.05	0.2	0.02	0.32
Irregular vessels in MD	0.5	0.24	0.03	0.36
Linear vessels in MD	0.45	0.39	0.24	0.63
Linear vessels in SD	0.73	0.22	0.29	0.65
Tree-like vessels in SD	0.18	0.33	0.11	0.49
Coma vessels in SD	0.77	0.94	0.85	0.91
Pigment in SD	0.73	0.73	0.53	0.86
MD: magnified dermoscopy; NPV: negative predictive value; PPV: positive predictive value; SD: standard dermoscopy.

DISCUSSION

Accurate differentiation between facial dermal nevi and basal cell carcinoma remains challenging in clinical practice, particularly when these lesions present with similar dermoscopic features. Our findings demonstrate that MD may reveal characteristic structures that are not visible with SD and enable easier differentiation between these 2 lesion types. In DN, magnified dermoscopy (Fig. 1B–C) revealed roundish structures homogeneously pigmented, or with a darker brownish rim at the periphery, corresponding in histology to melanocytes arranged in dermal nests (4). Roundish structures are clearly visible under MD because DN generally show no junctional activity and overlying epidermis lacking pigmentation allows visualization of the underlying dermal melanocytes. However, in 6 (27.2 %), more pigmented DN, polygonal structures corresponding to pigmented keratinocytes were also visible (Fig. 1D). What should be emphasized is that no roundish structures were observed in any of the analyzed BCCs.

Although benign pigmented melanocytes may occasionally colonize BCC nests, they appear as solitary dendritic cells and tend to be sparse (5). This likely explains why roundish structures are not visible in MD of BCC.

Importantly in BCC, pigmentation is mainly due to the presence of melanin within the tumour cells and melanophages that commonly merge with or cluster around the tumuor nests (5, 6). In our study in BCC structures with fading borders, corresponding to melanophages were observed (Fig. 1F). Moreover, they were observed in both DN and BCC, as melanophages may be present in all skin lesions where melanin is present.

Furthermore, in BCC MD showed significantly more vessels including new ones not visible in SD namely irregular and looped vessels. Our observations revealed a significantly higher number of blood vessels in BCC compared to DN, particularly irregular and arborizing ones which may confirm angiogenesis in the neoplastic lesion. Our findings are consistent with the results of so far, the only study on BCC in MD which showed significantly more vessels, including a new type of them not visible at standard magnification (7).

In conclusion, our findings suggest that MD may be a useful adjunctive tool in the differential diagnosis between DN and BCC. Roundish structures appear to be a characteristic MD feature of DN and demonstrated the highest diagnostic performance, with very high sensitivity and perfect specificity. In contrast, the presence of arborizing or irregular vessels in MD strongly favours the diagnosis of BCC. Moreover, BCC lesions are characterized by the absence of roundish structures and by a higher number of irregular, linear and looped vessels. Although these results highlight the potential diagnostic value of MD in distinguishing DN from BCC, further studies with larger cohorts are needed to validate these findings.

REFERENCES

1. Greco V, Cappello M, Megna M, Costa C, Villani A, Fabbrocini G, et al. Dermoscopic patterns of intradermal naevi. Australas J Dermatol 2020; 61: 337–341. https://doi.org/10.1111/ajd.13366
2. Pogorzelska-Dyrbuś J, Cinotti E, Lallas A. Differentiation of dermal nevus and basal cell carcinoma based on optical-super high magnification dermoscopy. Dermatol Pract Concept 2024; 14: e2024094. https://doi.org/10.5826/dpc.1401a94
3. Guida S, Pogorzelska-Dyrbuś J, Radi G, Giuffrida R, Karls R, Daviti M, et al. Magnified dermoscopy terminology for skin tumours: International Dermoscopy Society Delphi consensus. J Eur Acad Dermatol Venereol 2025; 39: e963–e966. https://doi.org/10.1111/jdv.20717
4. Pogorzelska-Dyrbuś J, Guida S, Radi G, Rossi R, Lallas A, Cinotti E. Correspondence of optical super-high magnification dermoscopy with histopathology of melanocytic lesions. Dermatol Pract Concept 2025; 15: 4817. https://doi.org/10.5826/dpc.1501a4817
5. Brankov N, Prodanovic EM, Hurley MY. Pigmented basal cell carcinoma: increased melanin or increased melanocytes? J Cutan Pathol 2016; 43: 1139–1142. https://doi.org/10.1111/cup.12819
6. Kirzhner M, Jakobiec FA. Clinicopathologic and immunohistochemical features of pigmented basal cell carcinomas of the eyelids. Am J Ophthalmol 2012; 153: 242–252. https://doi.org/10.1016/j.ajo.2011.07.008
7. Pogorzelska-Dyrbuś J, Lallas A, Szepietowski JC. Morphology of vessels in basal cell carcinoma in optical super-high magnification dermoscopy. Acta Derm Venereol 2023; 103: adv11966. https://doi.org/10.2340/actadv.v103.11966