A comparative analysis of clinical and sonographic features: cutaneous melanoma and melanocytic nevi

Introduction

Skin thickness varies by anatomical site and is an important parameter in the evaluation of skin diseases. The skin serves as the primary barrier against external insults and pathogens (1). As an organ rich in melanocytes, the skin is a common site for melanocytic tumors, among which melanoma is one of the most clinically significant.

Melanoma can arise in any organ containing melanocytes, including the eye, meninges, and mucosal surfaces. However, it is most frequently encountered in the skin and represents a highly aggressive malignancy associated with significant mortality (2). According to 2020 global cancer statistics, there were 324,635 new cases of melanoma, accounting for 1.7% of all new cancer cases, with 57,043 deaths attributed to the disease, representing 0.6% of cancer-related fatalities (3). A study by Yu et al. found that in 2024, the age-standardized prevalence rate (ASIR) of melanoma in China was 0.7 per 100,000, representing an 89.2% increase since 1990, a rate four times the global average (4). Cutaneous melanoma (CM) refers to a malignant proliferation of melanocytes within the skin and includes subtypes such as superficial spreading, nodular, acral lentiginous, and lentigo maligna melanoma. CM is among the most aggressive skin tumors, with the potential for lymphatic and hematogenous metastasis. Although its prevalence rate is relatively low, CM accounts for up to 73% of skin cancer-related deaths (5).

Melanocytic nevi (MN) can be classified as congenital or acquired (6). Acquired MN, which are more common and occur throughout childhood and adulthood with a peak prevalence around age 30 years (7), are histologically classified into three subtypes based on the depth of melanocytic nests: junctional nevi, compound nevi, and intradermal nevi. These different histological subtypes carry varying risks of progression to melanoma (8), with approximately 33% of malignant melanoma (MM) arising from the malignant transformation of benign MN (9). A diagnosis of melanoma imposes significant psychological and socioeconomic burdens on patients (10). Therefore, early and accurate differentiation between CM and cutaneous melanocytic nevi (CMN) using high-frequency ultrasound (HFUS) is essential for guiding clinical management, reducing disease-specific mortality, improving survival rates, and enhancing prognosis.

As a non-invasive, real-time, and repeatable imaging modality, HFUS has become an important adjunctive tool for skin tumor evaluation. HFUS provides multidimensional information from the epidermis to the subcutaneous tissue, offering critical insights for differentiating benign from malignant melanocytic skin lesions. While numerous studies have reported on the dermoscopic features of CM and CMN (11-15), data regarding their sonographic characteristics and comparative analysis remain limited. This retrospective study analyzed the differences in clinical and sonographic features between pathologically confirmed CM and CMN, aiming to provide a reference for clinical differential diagnosis, explore the utility of HFUS, and offer insights for early clinical diagnosis. We present this article in accordance with the STARD reporting checklist (available at https://tcr.amegroups.com/article/view/10.21037/tcr-2026-0511/rc).

Methods

Patient population

This retrospective study analyzed data from patients treated at the Department of Ultrasound, West China Hospital, Sichuan University, between January 2019 and April 2024, including nine patients with CM, 11 with compound nevi, and 22 with intradermal nevi. The study protocol was approved by the Institutional Review Board of West China Hospital, Sichuan University. All cases were confirmed by surgical pathology and had available preoperative high-frequency color Doppler ultrasound records. Inclusion criteria were: (I) all patients underwent a preoperative ultrasound examination; (II) the skin lesions identified on ultrasound were consistent with histopathological findings. Exclusion criteria were: (I) patients with incomplete clinical or imaging data; (II) cases where the ultrasound findings were inconsistent with the histopathological results. The study was conducted in accordance with the Declaration of Helsinki and its subsequent amendments. The study was approved by the Ethics Committee of West China Hospital of Sichuan University [approval No. 2026(376)]. Informed consent was obtained from all volunteers.

Analysis of ultrasound imaging data

This was a retrospective study. All ultrasound examinations and stored images were acquired using Philips iU22, Philips EPIQ5, or Philips EPIQ7 color Doppler ultrasound systems, all uniformly equipped with L12–5 (frequency 5–12 MHz) and eL18–4 (frequency 4–18 MHz) linear array transducers. For image analysis, two attending physicians, each with over 5 years of experience in superficial tissue ultrasound, independently and retrospectively evaluated the ultrasound images in a double-blind manner, unaware of the final pathological diagnoses. Grayscale and color Doppler blood flow features were analyzed and recorded sequentially. On grayscale ultrasound, the following features were assessed and recorded: lesion location, depth of skin involvement, maximum diameter (<1 /≥1 cm), margin (well-defined, poorly defined, or ill-defined), morphology (relatively regular, slightly irregular, or irregular), and the presence of hyperechoic spots, posterior acoustic enhancement, and lateral acoustic shadow. On color Doppler flow imaging (CDFI), intralesional blood flow was evaluated and graded according to the Adler semi-quantitative criteria (16): grade 0 (no detectable blood); grade I (minimal flow, with 1–2 punctate or linear signals); grade II (moderate flow, with 3–4 punctate signals or one distinct vessel); grade III (abundant flow, with ≥5 punctate signals or ≥2 distinct vessels). In cases of initial disagreement, a third qualified ultrasound physician provided an independent assessment, and a consensus was reached.

Statistical analysis

Statistical analyses were performed using SPSS Statistics (v29.0; IBM Corp., Armonk, NY, USA). Continuous data not conforming to a normal distribution were expressed as median with interquartile range (IQR). Categorical data were shown as n (%). Comparisons of categorical data were performed using the chi-square (χ²) test or Fisher’s exact test. Receiver operating characteristic (ROC) curves were constructed, and the area under the curve (AUC) was calculated to assess the diagnostic value of age, maximum diameter, and their combination in differentiating CM from CMN and compound nevi from intradermal nevi. P<0.05 indicated that the difference was statistically significant.

Results

Comparison of clinical and sonographic characteristics between CM and CMN

Table 1 compares the clinical and sonographic characteristics of CM and CMN. Patients with CM were significantly older than those with CMN (P<0.05), whereas gender distribution did not differ significantly between the two groups (P>0.05). Lesion location also differed significantly, with CM predominantly arising on the extremities and CMN most frequently arising on the face, head, and neck (P<0.05). Breslow thickness data were available for 4 of the 9 CM cases, with values of 7, >8, 10, and 10 mm, all of which were thick melanomas (≥7 mm). Regarding depth of invasion, all CM lesions extended to the subcutaneous layer, whereas CMN lesions were confined to the dermis (P<0.05). The majority of CM lesions measured ≥1 cm in maximum diameter, whereas most CMN lesions were <1 cm (P<0.05). CM lesions more frequently exhibited poorly defined margins and irregular or slightly irregular morphology, whereas CMN lesions predominantly showed well-defined margins and regular morphology (both P<0.05). Posterior acoustic enhancement was observed in the vast majority of CM lesions but absent in all CMN lesions (P<0.05). No significant differences were found between the two groups regarding hyperechoic spots or lateral acoustic shadow (both P>0.05). Abundant blood flow signals were detected in all CM lesions (Figure 1), whereas the majority of CMN lesions showed non-abundant signals (P<0.05). The prevalence of CMN (33/42, 78.6%) was higher than that of CM (9/42, 21.4%).

Figure 1 Representative HFUS and histopathological images of three melanocytic lesions: cutaneous melanoma (A-C), compound nevus (D-F), and intradermal nevus (G-I). HFUS and histopathological images of left foot CM in a 64-year-old male. (A) Cutaneous and subcutaneous layer involvement, poorly defined margins, irregular morphology, punctate hyperechoic spots, mild posterior acoustic enhancement, no lateral acoustic shadowing. (B) Abundant intralesional blood flow signals. (C) CMM histopathology (HE staining, ×100): nested atypical melanocytes in epidermis, dermis and subcutaneous layers. HFUS and histopathological images of a compound nevus on the ulnar right hand dorsum in a 3-year-old female. (D) Superficial dermis involvement, relatively well-defined margins, relatively regular morphology, no posterior acoustic enhancement, no lateral acoustic shadowing. (E) No intralesional blood flow signals. (F) Compound nevus histopathology (HE staining, ×200): nevus cells in nests at the dermo-epidermal junction and dermis. HFUS and histopathological images of an intradermal nevus on the left neck in a 53-year-old male. (G) Full-thickness dermis involvement, relatively well-defined margins, relatively regular morphology, no posterior acoustic enhancement, no lateral acoustic shadowing. (H) Sparse intralesional blood flow signals. (I) Intradermal nevus histopathology (HE staining, ×200): nevus cells within the dermal layer. CM, cutaneous melanoma; HE, hematoxylin and eosin; HFUS, high-frequency ultrasound.

Diagnostic performance of clinical and sonographic features in differentiating CM from CMN

ROC curve analysis was performed to evaluate the diagnostic performance of patient age, maximum diameter, and their combination in distinguishing CM from CMN. All three parameters showed statistically significant diagnostic value (all P<0.05). The combined model achieved a sensitivity comparable to that of patient age alone and was superior to that of maximum diameter alone, and demonstrated a specificity of 100%, which surpassed both individual parameters. The AUC of the combined model was comparable to that of patient age alone. The combination of age and maximum diameter yielded optimal diagnostic performance (Table 2, Figure 2).

Figure 2 ROC curves for the diagnosis of CM and CMN by patient age, maximum diameter, and their combination. CM, cutaneous melanoma; CMN, cutaneous melanocytic nevi; ROC, receiver operating characteristic.

Comparison of clinical and sonographic characteristics among CM, compound nevi, and intradermal nevi

Table 3 compares the clinical and sonographic characteristics of CM, compound nevi, and intradermal nevi. Age distribution differed significantly among the three groups (P<0.05), whereas gender distribution did not (P>0.05). Lesion location also differed significantly, with CM predominantly arising on the extremities, whereas both compound and intradermal nevi most frequently arising on the face, head, and neck (P<0.05). Regarding depth of invasion, all CM lesions extended to the subcutaneous layer, whereas compound and intradermal nevi were confined to the dermis, with compound nevi more commonly involving the superficial dermis and intradermal nevi more frequently involving the full-thickness dermis (P<0.05). The majority of CM lesions measured ≥1 cm in maximum diameter, whereas most compound and intradermal nevi were <1 cm (P<0.05). CM lesions more frequently exhibited poorly defined margins and irregular or slightly irregular morphology. In contrast, all compound and intradermal nevi presented with well-defined margins and regular morphology (both P<0.05). Posterior acoustic enhancement was observed in the vast majority of CM lesions but absent in all compound and intradermal nevi (P<0.05). No significant differences were found among the three groups regarding hyperechoic spots or lateral acoustic shadow (both P>0.05). Abundant blood flow signals were detected in all CM lesions, whereas the majority of compound nevi (Figure 1D,1E) and intradermal nevi (Figure 1G,1H) showed non-abundant signals (P<0.05). The prevalence of intradermal nevi (22/33, 66.7%) was higher than that of compound nevi (11/33, 33.3%).

Diagnostic performance of clinical and sonographic features in differentiating compound nevi from intradermal nevi

ROC curve analysis was performed to evaluate the diagnostic performance of patient age, maximum diameter, and their combination in differentiating compound nevi from intradermal nevi. Patient age alone and the combined model each showed very low discriminatory performance (both P<0.05), with a sensitivity of 0 for both. Maximum diameter alone yielded an AUC of 0.661, though this was not statistically significant (P>0.05). The combination of age and maximum diameter did not improve diagnostic efficacy over age alone (Table 4, Figure 3).

Figure 3 ROC curves for the diagnosis of compound nevi and intradermal nevi by patient age, maximum diameter, and their combination. ROC, receiver operating characteristic.

Discussion

As the body’s largest organ, the skin is frequently affected by a wide range of diseases with high prevalence, diverse clinical presentations, and multifactorial etiologies, which collectively contribute to diagnostic challenges. This study summarized and analyzed the sonographic features of two groups (CM and CMN) and three groups (CM, intradermal nevi, and compound nevi) under HFUS. By analyzing differences in the depth of involvement and internal ultrasound characteristics, this study aimed to provide additional information for differentiating benign from malignant melanocytic skin lesions. These insights may enhance clinicians’ understanding and support more accurate selection and application of treatment strategies.

CM and CMN can occur anywhere on the body. In this study, CM was most frequently found on the extremities (77.8%), while CMN was most commonly located on the face (39.3%) and the head and neck (non-facial area, 30.3%). Among CMN subtypes, compound nevi were most frequently observed on the face (36.3%) and the head and neck (non-facial area, 27.3%), and intradermal nevi were most common on the face (40.9%) and the head and neck (non-facial area, 31.8%). The higher prevalence of CM on the extremities may be associated with factors such as sun exposure on acral skin. The higher prevalence of CMN in the head and neck region may be attributed to greater visibility of nevi in these areas, prompting aesthetic or health-related concerns. Previous studies have found that differences in distribution between mountain and coastal residents may lie in anatomical location, with the former more commonly located on the head or neck and the latter on the trunk and extremities (17). Risk factors for CM development include chronic ultraviolet (UV) exposure, family history, chemical carcinogens, and immunosuppressants. As a primary environmental risk factor for melanoma, UV radiation may contribute to geographical variations in melanoma prevalence. However, this study did not explore differences in the anatomical distribution of melanoma; future research should conduct more detailed analyses of melanoma prevalence by anatomical site and geographical distribution to better understand its epidemiological characteristics.

CM and CMN exhibit significant differences in several aspects of their HFUS images. This study provides key evidence for their differential diagnosis by analyzing these distinctions. CM primarily occurred in the elderly population aged ≥60 years (77.8%), while CMN was predominantly observed in younger individuals aged ≤40 years (84.8%). Regarding maximum diameter (≥1 cm), CM (77.8%) had a significantly higher proportion of such lesions than CMN (24.2%). CMN most frequently involved the full-thickness dermis (51.5%), followed by the superficial dermis (48.5%). The prevalence of CMN (33/42, 78.6%) was higher than that of CM (9/42, 21.4%). Regarding the two subtypes of MN, compound nevi and intradermal nevi predominantly occur in younger individuals aged ≤40 years, and the prevalence of intradermal nevi (22/33, 66.7%) was higher than that of compound nevi (11/33, 33.3%). CM (77.8%) had a significantly higher proportion of lesions with a maximum diameter (≥1 cm) compared to compound nevi (18.2%) and intradermal nevi (27.3%). Regarding the depth of involvement, compound nevi most commonly involved the superficial dermis (72.7%), followed by the full-thickness dermis (27.3%), whereas intradermal nevi most frequently involved the full-thickness dermis (63.6%), followed by the superficial dermis (36.4%). These findings indicate that CM tends to occur in older individuals and presents as larger, more deeply invasive lesions. A study by Yu et al. found that among individuals aged <60 years, melanoma was more common in males, whereas in those aged >60 years, the prevalence was higher in females (4). This aligns with our findings, where 5 out of 7 patients aged ≥60 years were female. MN are present at birth or appear in early childhood, with numbers gradually increasing to a peak around the age of thirty, after which they tend to undergo gradual involution; adolescence represents a period of rapid development for these lesions (7,18). In this study, 84.8% (28/33) of patients developed MN before the age of 40 years, and 96.9% (32/33) developed them before the age of 60 years, which is consistent with previous research. Our findings on maximum diameter are also consistent with previous research. Li et al. found that among 381 patients with congenital nevi, 298 cases (78.2%) had a maximum diameter of less than 1.5 cm (18). A study by Wang et al., which examined 85 cases of CMN, found that compound nevi involve both the epidermis and dermis, while intradermal nevi are located within the dermis (19). This finding is largely consistent with the results of the present study. The lack of detectable epidermal involvement in compound nevi in the present study may be attributed to their use of an ultra-high frequency transducer (frequency 50 MHz) offering superior resolution. Additionally, such ultra-high frequency transducers are more effective for detecting internal punctate hyperechoic spots within lesions. In this study, we obtained histopathological images from one case of compound nevus (Figure 1F) and one case of intradermal nevus (Figure 1I), which provided corroborative evidence for our sonographic analysis. The histopathological image of the compound nevus demonstrated nests of nevus cells located at the dermo-epidermal junction and within the dermis, while the nevus cells of the intradermal nevus were located within the dermis. In this study, the prevalence of intradermal nevi was significantly higher than that of compound nevi, with a median age of 37 years (range, 33.75–40 years). In contrast, a study by Liu et al. reported that the predominant histological subtype of MN in children aged 1–3 years was junctional nevi, while intradermal nevi were predominant in children aged 7–12 years. This discrepancy is likely attributable to differences in the study populations. The present study included a wider age range, demonstrating that the prevalence of different MN subtypes varies across different age groups (10). The significantly larger maximum diameter and greater depth of invasion observed in CM in our study reflect its malignant and infiltrative biological behavior (20). These aggressive sonographic features correlate with the histopathological features of CM, which shows nests of atypical melanocytes within the epidermis, dermis, and subcutaneous layer (Figure 1C), aiding in the distinction from benign melanocytic lesions.

Regarding margin and morphology characteristics, CM most commonly demonstrated poorly defined margins (55.6%) and exhibited either slightly irregular (44.4%) or irregular (44.4%) morphology. In contrast, CMN demonstrated well-defined margins (90.9%) and relatively regular morphology (100%). Compound nevi exhibited well-defined margins (72.7%) and relatively regular morphology (100%), and intradermal nevi showed well-defined margins (100%) and relatively regular morphology (100%). A study by Qin et al. involving 106 cases of MN found that under HFUS, the majority demonstrated well-defined margins (95/106, 89.6%) and regular morphology (101/106, 95.3%) (21). Wang et al. reported that compound nevi appeared as elevated oval or strip-like hypoechoic structures infiltrating both the epidermis and dermis, often exhibiting a “straw-hat” sign, while intradermal nevi appeared as oval hypoechoic structures within the dermis, with 34.8% showing a “mushroom” sign (19). These findings are consistent with our observation that CMN generally have well-defined margins and regular morphology. Posterior acoustic enhancement was present in most CM (88.9%), with all cases (100%) showing abundant blood flow signals. Posterior acoustic enhancement was absent in all CMN cases (100%), and non-abundant blood flow signals were found in 78.8% of CMN cases. Both compound nevi and intradermal nevi showed absent posterior acoustic enhancement (100% for each). Non-abundant blood flow signals were noted in 72.7% of compound nevi and 81.8% of intradermal nevi. Most CM (77.8%) and CMN (90.9%) exhibited an absence of hyperechoic spots, as did most compound nevi (90.9%) and intradermal nevi (90.9%). Hyperechoic spots within MN are presumed to be associated with focal melanin accumulation. In this study, most CM and CMN cases did not exhibit these hyperechoic spots, and no statistically significant difference was observed between the two groups. This suggests that the presence of internal punctate hyperechoic foci may not be a strong characteristic indicator of CM and has limited value in distinguishing CM from CMN (21). Regarding hemodynamics, the higher detection rate and intensity of blood flow signals in CM compared to CMN may be closely related to tumor angiogenesis induced by vascular endothelial growth factor (VEGF) secreted by melanoma cells.

This study used ROC curve analysis to evaluate the diagnostic value of patient age and maximum diameter in differentiating between CM and CMN, as well as between compound nevi and intradermal nevi. The results revealed significant differences in the diagnostic performance of these two indicators across the different types of lesions. Patient age served as a highly effective standalone indicator for distinguishing CM from CMN, with an AUC of 0.928 [95% confidence interval (CI): 0.798–1.000], demonstrating both high sensitivity (88.9%) and high specificity (97.0%). Advancing age was associated with an increased likelihood of a CM diagnosis. Maximum diameter also demonstrated good discriminative value, with an AUC of 0.882 (95% CI: 0.763–1.000), a sensitivity of 77.8%, and a specificity of 81.8%. A larger maximum diameter was associated with a higher probability of a CM diagnosis. The combination of patient age and maximum diameter yielded a slightly increased AUC of 0.929 (95% CI: 0.796–1.000) and elevated specificity to 100%, while maintaining a high sensitivity of 88.9%. This suggests that for older patients with a larger lesion diameter, the combined use of these two indicators can help reduce the likelihood of misdiagnosis, providing a reliable basis for the early, accurate diagnosis of CM and timely clinical intervention. Patient age demonstrated no clinical diagnostic value in differentiating compound nevus from intradermal nevi, with an AUC of 0.153 (95% CI: 0.001–0.311), a sensitivity of 0, and a specificity of 95.5%. This indicates a high degree of overlap in the age distribution between compound and intradermal nevi, and age cannot serve as a discriminative parameter for distinguishing between them. Maximum diameter provided a certain diagnostic value for differentiating compound nevus from intradermal nevi, with an AUC of 0.661 (95% CI: 0.467–0.855), a sensitivity of 63.6%, and a specificity of 68.2%. This suggests that a measurable difference in maximum diameter exists between the two entities, and this parameter can assist in their distinction. However, its discriminative ability remains moderate, and diagnostic accuracy should be further enhanced by incorporating additional sonographic features. The combination of patient age and maximum diameter failed to enhance diagnostic performance, yielding an AUC of 0.145 (95% CI: 0.005–0.284), a sensitivity of 0, and a specificity of 95.5%. This performance was essentially equivalent to that of patient age alone, further confirming that adding the age parameter provided no auxiliary benefit for diagnosis and, in fact, attenuated the discriminative value of maximum diameter.

HFUS, as a non-invasive, real-time, and convenient imaging method, can directly and accurately display skin layers, the sonomorphological features of various lesions, and the depth of vertical invasion, thereby providing important auxiliary information for lesion differentiation. However, its limitations include restricted penetration depth, insufficient resolution for detailed skin microstructure, and the potential to prolong diagnostic workup, which may delay surgical excision of suspicious lesions when relied upon as an adjunctive imaging tool. As a single technique cannot meet all diagnostic needs in dermatology, the combined application of multimodal imaging, such as dermoscopy, confocal laser scanning microscopy (CLSM), and ultra-high frequency ultrasound (UHFUS), is key to enhancing diagnostic accuracy and efficiency. These techniques can obtain multidimensional information from the epidermis to the subcutaneous tissue, significantly improving early detection, precise subtyping, accurate margin delineation, treatment monitoring, and prognosis assessment in skin diseases.

In the clinical management of melanoma, HFUS has significant value for preoperative diagnosis, staging, and treatment planning (22). The surgical margin for melanoma excision should be determined based on Breslow thickness, which is defined as the vertical distance measured from the granular layer of the epidermis (or from the base of an ulcer if present) to the deepest point of tumor invasion. This parameter is a key factor in guiding treatment and assessing prognosis (23). In this study, Breslow thickness data were available for 4 of the 9 CM cases, with values of 7, >8, 10, and 10 mm, all of which were thick melanomas (≥7 mm). Among the common clinicopathological subtypes, such thickness is more often seen in nodular melanoma and acral lentiginous melanoma. Of note, all nine lesions in this study showed subcutaneous invasion on ultrasound, a feature that is highly consistent with the biological behavior of thick melanoma. However, due to the limitations inherent to the retrospective study design, Breslow thickness data could not be obtained for the remaining 5 cases. In addition, thin melanomas were not included in this cohort, which represents a major limitation of this study. Future prospective studies are needed to better characterize the ultrasound features of melanomas across different Breslow thicknesses. Additionally, percutaneous contrast-enhanced ultrasound has been demonstrated to predict sentinel lymph node metastasis in patients with lower extremity melanoma, offering a practical imaging tool for further assessment of melanoma (24).

This study has several limitations. First, as a single-center retrospective analysis, it only included lesions from patients who underwent surgical excision and histopathological examination. This focus on excised nevi may introduce selection bias. Second, the relatively small sample size may further increase selection bias and potentially limit the generalizability of the findings to the broader population of melanocytic lesions in China. Furthermore, the assessment of very small lesions (diameter <3 mm) was limited due to suboptimal visualization on ultrasound.

Conclusions

Through a retrospective analysis of the sonographic differences between CM and CMN, this study confirms the significant clinical value of HFUS in their differential diagnosis. CM predominantly occurs in elderly individuals, on the extremities. On ultrasound, CM is characterized by involvement of the full-thickness dermis and subcutaneous layer, a maximum diameter of ≥1 cm, poorly defined margins, an irregular or slightly irregular morphology, posterior acoustic enhancement, and abundant blood flow signals. In contrast, CMN predominantly affects younger individuals, most frequently on the head, neck, and face. On ultrasound, compound nevi typically involve the superficial dermis, while intradermal nevi most commonly involve the full-thickness dermis. Both types of CMN exhibit a maximum diameter of <1 cm, relatively well-defined margins, relatively regular morphology, absence of posterior acoustic enhancement, and non-abundant blood flow signals. Both patient age and maximum diameter are effective parameters for differentiating CM from CMN. Among them, the combination of age and maximum diameter yields the optimal diagnostic performance for distinguishing CM from CMN, achieving a specificity of 100%. For differentiating compound nevi from intradermal nevi, maximum diameter alone affords a certain reference value. HFUS can assist in qualitative diagnosis and allows for precise measurement of lesion thickness, assessment of invasion depth, and evaluation of regional lymph nodes. This provides valuable clinical guidance for surgical planning and prognosis evaluation. However, to improve diagnostic accuracy, HFUS findings should be integrated with clinical features, patient history, and other multimodal imaging modalities. Future research should focus on multi-center, large-scale studies to refine sonographic diagnostic criteria and incorporate emerging technologies to enable more precise diagnosis and assessment.

Acknowledgments

None.

Footnote

Reporting Checklist: The authors have completed the STARD reporting checklist. Available at https://tcr.amegroups.com/article/view/10.21037/tcr-2026-0511/rc

Data Sharing Statement: Available at https://tcr.amegroups.com/article/view/10.21037/tcr-2026-0511/dss

Peer Review File: Available at https://tcr.amegroups.com/article/view/10.21037/tcr-2026-0511/prf

Funding: This study was supported by the National Key Research and Development Program, China (No. 2023YFC2410802); Natural Science Foundation, China (No. 82572249); and Science and Technology Support Program of Sichuan Province, China (No. 2025YFHZ0232).

Conflicts of Interest: All authors have completed the ICMJE uniform disclosure form (available at https://tcr.amegroups.com/article/view/10.21037/tcr-2026-0511/coif). The authors have no conflicts of interest to declare.

Ethical Statement: The authors are accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved. The study was conducted in accordance with the Declaration of Helsinki and its subsequent amendments. The study was approved by the Ethics Committee of West China Hospital of Sichuan University [approval No. 2026(376)]. Informed consent was obtained from all volunteers.

Open Access Statement: This is an Open Access article distributed in accordance with the Creative Commons Attribution-NonCommercial-NoDerivs 4.0 International License (CC BY-NC-ND 4.0), which permits the non-commercial replication and distribution of the article with the strict proviso that no changes or edits are made and the original work is properly cited (including links to both the formal publication through the relevant DOI and the license). See: https://creativecommons.org/licenses/by-nc-nd/4.0/.

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