High-Frequency Ultrasound and Shear Wave Elastography in Quantitative Differential Diagnosis of High-Risk and Low-Risk Basal Cell Carcinomas

Seeing beyond skin deep: High-resolution ultrasound in dermatology-A comprehensive review and future prospects

High-resolution ultrasound (HRUS), operating at frequencies of 20-25 MHz, is a non-invasive imaging tool that offers dermatologists the ability to visualize structures beneath the skin surface. The objective of this review is to present a comprehensive overview of HRUS applications, emphasising its utility in diagnosing, characterising and managing various dermatological conditions. We undertook a comprehensive literature review on the dermatological application of HRUS across Medline, Embase and Cochrane Library databases, while also incorporating our own clinical experience of over 16 years with the tool. In normal skin, the epidermis and dermis are hyperechoic, and the subcutaneous layer is hypoechoic. Basal cell carcinomas appear hypoechoic with irregular margins, while the presence of hyperechoic inclusion bodies suggests aggressive pathology. Squamous cell carcinomas pose challenges due to acoustic shadow artefacts from the thickened stratum corneum. Melanomas are homogenous hypoechoic lesions, with HRUS used to accurately predict Breslow thickness. HRUS provides dermatologists with a valuable adjunct to traditional clinical examination. Future advancement in image resolution and the standardisation of diagnostic parameters may further expand its utility.

Correlation of ultrasound features with Bcl-2 protein expression in basal cell carcinomas (BCCs)

BACKGROUND

The expression of the Bcl-2 protein is frequently observed in basal cell carcinomas (BCCs), making it a significant biological marker and potential therapeutic target. Skin ultrasonography offers a noninvasive means of obtaining anatomical information about cutaneous tumors.

OBJECTIVES

The purpose of this study was to investigate the correlation between ultrasound features and Bcl-2 expression in BCCs, to provide a reference for developing pharmacological treatment plans.

METHODS

According to the Bcl-2 protein expression, 74 BCCs confirmed by surgical pathology were divided into high Bcl-2 expression BCCs (HB-BCCs) and low Bcl-2 expression BCCs (LB-BCCs). Preoperative lesion ultrasound features were analyzed retrospectively based on Liang's criteria, which included the following features: shape, surface, keratinization, base, infiltration level, internal echogenicity, distribution of hyperechoic spots, posterior echogenic changes, internal Doppler signal, and lesion size (maximum diameter and infiltration depth). The differences of two groups were compared using a chi-square test or a paired t-test.

RESULTS

Based on ultrasound features, cystic areas were more frequent in LB-BCCs (χ2  = 7.015, P = .008). Furthermore, LB-BCCs exhibited greater infiltration depth than HB-BCCs (4.86 ± 2.12 mm vs. 2.72 ± 1.40 mm, P = .000), had a higher propensity to infiltrate the subcutaneous tissue (χ2  = 12.422, P = .002), and displayed a more abundant internal Doppler signal within the lesions (χ2  = 24.696, P = .000). Conversely, maximum diameter of the lesions, shape, surface, keratinization, base, hyperechoic spots distribution, and posterior echogenic changes of the lesions did not differ significantly between the two groups.

CONCLUSIONS

Ultrasound features are correlated with Bcl-2 protein expression level in BCCs. LB-BCCs show greater infiltration depth, subcutaneous infiltration, more cystic changes and more abundant internal Doppler signal than HB-BCCs, which may suggest a potential basis for drug selection in BCC chemotherapy.

Usefulness of Shear Wave Elastography in Determining the Tumor Extent of Basal Cell Carcinomas

OBJECTIVES

The purpose of this study was to investigate the value of shear wave elastography (SWE) in determining tumor extent of basal cell carcinomas (BCC), and thereby determine the optimal surgical margins (OSM).

METHODS

10 patients (40 surgical margins) with BCC were collected, the visual observation boundaries (VOB) were marked, and the SWE parameters of soft tissues were measured 1 mm intervals in "3, 6, 9, 12" clock directions, starting from VOB. Then tumors were resected with a 5 mm surgical margin outward expansion of VOB. All specimens were examined pathologically 1 mm intervals from VOB in four clock directions. With the positive margins furthest from the tumor as the real tumor boundaries (RTB) and the negative margins closest to the tumor as the optimal surgical margins (OSM). The SWE parameters were compared between these two groups.

RESULTS

The elasticity ratio (E_ratio ) of average young's modulus between region of interest and adjacent normal soft tissue had statistically significant differences between groups (P = .000), while other parameters show no difference. The E_ratio of RTB and OSM were 1.22 ± 0.14 and 0.99 ± 0.07. The area under the ROC curve was .947. Taking 1.075 as the threshold of E_ratio for the diagnosis of tumor extent, the sensitivity, specificity and accuracy were 87.5%, 90.0% and 90.0%. The surgical margins designed according to OSM were better than those designed according to VOB + 5 mm (P = .000).

CONCLUSIONS

The E_ratio of SWE is helpful in determining tumor extent of BCC. This is beneficial for surgical margin designing.