A comparative study of melanocytic nevi classification with dermoscopy and high‐frequency ultrasound

Abstract

Background: Melanocytic nevi (MN) can be classified into three subtypes according to the depth of the nests of nevus cells which is important for management. Highfrequency ultrasound (HF-US) can clearly reveal the lesion size, contour, depth, and internal structures. However, the HF-US studies of MN according to subtypes are limited. We aimed to describe the HF-US features of MN and explore its value in accurate classification. Materials and methods:This retrospective study was conducted from January 2018 to November 2019. Eighty-five patients with MN were included and examined by 50 and 20 MHz HF-US. The HF-US features were recorded including morphological flatness, depth, shape, boundary, internal echogenicity, hyperechoic spots, lateral acoustic shadow, posterior echoic patterns, mushroom signs, and straw-hat signs. Each image was evaluated by two physicians independently, and the consistency was tested.Results: Eleven lesions could not be detected by HF-US. The rest 74 lesions underwent ultrasonic analysis. MN appeared as strip-shaped or oval, hypoechoic areas localized in the epidermis and dermis under ultrasonography. A strong consistency between HF-US and dermoscopy of determining the lesion depth was achieved (κ = 0.935, p < 0.001).The hyperechoic spots were found in 57.6% intradermal nevi. The mushroom signs were seen in 34.8% intradermal nevi, and the straw-hat signs were seen in all the compound nevi. Conclusion:MN can be correctly classified using HF-US, and it had a strong correlation with dermoscopic and clinical classification. HF-US could further reveal the internal morphological features of MN, which may support more precise classification and management.

Noninvasive imaging exploration of phacomatosis pigmentokeratotica using high‐frequency ultrasound and optical coherence tomography: Can biopsy of PPK patients be avoided?

“…Since junctional nevi do not penetrate the dermis, visualization of these lesions was more challenging. On HFUS, we have observed the hypoechoic strip sign, which correlates well with the literature on discerning junctional nevi from other benign nevi subtypes 18 . The thin nature of junctional nevi on HFUS may be related to the restricted melanocytic proliferations at the DEJ.…”

“…The HFUS image (Figure 6B) demonstrates a thin 8 mm wide, 0.15 mm depth, and hypoechoic strip immediately below the epidermal entrance signal. The hypoechoic lesion (L) extends horizontally to either side but does not extend into the dermis below, correlating to the junctional nature of this pigmented lesion 18 . Throughout the image, the dermis remains architecturally intact without structural effacement.…”

“…The hypoechoic lesion (L) extends horizontally to either side but does not extend into the dermis below, correlating to the junctional nature of this pigmented lesion. 18 Throughout the image, the dermis remains architecturally intact without structural effacement. Underlying the dermis, the subcutaneous tissue (SC) and fascia (Fas) can be appreciated.…”

“…The hypoechoic lesions imaged in our study demonstrated heterogeneity with small hyperechoic spots within, potentially suggesting areas of melanin accumulation. 18 On OCT images, compound nevi have distinct features of elongated rete ridges with extension into the papillary dermis with occasional rete ridge fusion and rectification. In deeply pigmented lesions such as the nevi on the chest (Figure 4C) and shoulder (Figure 5C), there is a loss of the DEJ signal intensity, with incurring homogenous blending of the epidermis into the dermis.…”

“…The papular variant of SLN, most commonly associated with patients with PPK, consists of junctional, compound, and dermal melanocytic nevi unevenly distributed within the light‐brown macular patch 17 . Junctional melanocytic nevi (Figure 1B) show discrete nests of melanocytes at the DEJ with common melanocytic nests densities at rete ridges 18 . Compound nevi (Figure 1C) differ from junctional nevi by the presentation of nests of uniform melanocytes in both the epidermis and dermis.…”