Clinical relevance of sonometry-derived tumour thickness in malignant melanoma--a statistical analysis

High-frequency ultrasound as a scientific tool for skin imaging analysis

Ultrasonic imaging is one of the most important diagnostic tools in clinical medicine due to its cost, availability and good correlation with pathological results. High-frequency ultrasound (HFUS) is a technique used in skin science that has been little explored, especially in comparison with other sites and imaging techniques. HFUS shows real-time images of the skin layers, appendages and skin lesions in vivo and can significantly contribute to advances in skin science. This review summarizes the potential applications of HFUS in dermatology and cosmetology, with a focus on quantitative tools that can be used to assess various skin conditions. Our findings showed that HFUS imaging is a reproducible and powerful tool for the diagnosis, clinical management and therapy monitoring of skin conditions. It is also a helpful tool for assessing the performance of dermatological products. This technique may eventually become essential for evaluating the performance of dermatological and cosmetic products.

High-Frequency Ultrasonography-Possibilities and Perspectives of the Use of 20 MHz in Teledermatology

High-frequency ultrasonography (HF-USG) is a non-invasive and in vivo method of visualization of the skin and upper part of subcutaneous tissue based on ultrasounds above 20 MHz. Although initially HF-USG was introduced to measure skin thickness, it currently gained widespread acceptance in dermato-oncology, primarily when used to determine skin tumor margins. Moreover, its application in different dermatology fields is known, particularly as a rapidly evolving method in the objective evaluation of the severity of various chronic skin diseases. Among different specialties, teledermatology belongs to leading and continually developing areas of successful telemedicine applications. Various skin conditions are visible to the human eye, which makes them particularly suitable for telemedicine. However, HF-USG enables specialists to look into deeper skin layers, thus extending diagnostic options. On the other hand, teledermatology creates the possibility of sending images for consultation and facilitates the therapeutic decision as HF-USG can be used in an asynchronous store and forward manner. It seems that HF-USG and teledermatology may be regarded as a truly matched pair. The aim of this work is to present current applications of 20-MHz ultrasonography in dermatology, including skin neoplasms and chronic skin diseases. Moreover, the authors aimed to analyze the possibilities of HF-USG use as a valuable tool in teledermatology, especially in diagnosing and monitoring patients suffering from long-lasting skin conditions.

Non-invasive imaging in dermatology and the unique potential of raster-scan optoacoustic mesoscopy

In recent years, several non‐invasive imaging methods have been introduced to facilitate diagnostics and therapy monitoring in dermatology. The microscopic imaging methods are restricted in their penetration depth, while the mesoscopic methods probe deeper but provide only morphological, not functional, information. ‘Raster‐scan optoacoustic mesoscopy’ (RSOM), an emerging new imaging technique, combines deep penetration with contrast based on light absorption, which provides morphological, molecular and functional information. Here, we compare the capabilities and limitations of currently available dermatological imaging methods and highlight the principles and unique abilities of RSOM. We illustrate the clinical potential of RSOM, in particular for non‐invasive diagnosis and monitoring of inflammatory and oncological skin diseases.

Current applications of high-frequency ultrasonography in dermatology

The era of ultrasounds in dermatology started in 1979, when pioneering use of 15 MHz by Alexander and Miller in measuring the skin thickness was introduced. Since then, some new applications of high-frequency ultrasonography (HF-USG) have emerged providing the clinicians with an extra hand in their everyday practice. The main advantages of HF-USG include the possibility of real-time imaging, measurements of morphological and physiological aspects of the skin, safety associated with the use of non-ionizing media as well as the lack of contraindications to its performance. Currently the main clinical use of HF-USG in dermatology regards preoperative assessment of the depth of invasion in melanomas and basal cell carcinomas. The ultrasound image analysis allows noninvasive follow-up of inflammatory skin diseases, like atopic dermatitis, psoriasis and may be used for monitoring effectiveness of therapy in skin lymphomas and sclerotic skin diseases.

High-Frequency Ultrasound Examination in the Diagnosis of Skin Cancer

Ultrasound above 14 MHz images epidermis, dermis, and subcutaneous tissues in real time. Tumor depth is ascertained with B-mode. Three-dimensional imaging depicts nonpalpable, in-transit, and satellite lesions. Doppler blood flow technologies measure tumor neovascularity and map vascular structures. Three-dimensional Doppler histogram reconstruction measures tumor aggression and metastatic potential proportional to the percentage of malignant vessels. Subcutaneous investigation reveals nonpalpable metastatic disease and nodal basin lymphadenopathy. Adjacent nerves may be studied. Preservation of the fat-fascia border refines surgical staging of deeper malignancies. Image-guided biopsy is facilitated. Treatment under image guidance is optimized with radiation and various photo and thermal technologies.

Preoperative assessment of skin tumor thickness and structure using 14-MHz ultrasound

OBJECTIVE

The aim of this study was to compare the relationship between skin tumor thickness and homogeneity and to evaluate the accuracy of 14-MHz ultrasound while measuring the thickness of different skin tumors.

MATERIAL AND METHODS

The ultrasonographic and histological analysis of 72 skin tumors was performed. Preoperative vertical tumor thickness (T) and structure of 12 melanomas, 34 melanocytic nevi and 26 basal cell carcinomas was assessed by 14-MHz ultrasonography. After the tumors were excised the vertical thickness measurement (Breslow index, pT) was performed by pathologist. According to the histological thickness all skin tumors were divided to thin (≤1mm) and thick (>1mm). The accuracy of the 14-MHz ultrasound measurements and correlation between the ultrasonographic and histological tumor thickness were estimated.

RESULTS

Homogeneous structure was assessed for all thin (≤1mm) and the majority (81.3%) of thick (>1mm) melanocytic skin tumors. Nonhomogeneous structure was estimated in thin and thick basal cell carcinomas, accordingly 42.9% and 31.9%. Measurements of T and pT correlated moderately in thick (>1mm) tumors (r=0.694), while in thin (≤1mm) tumors correlation was low (r=0.336). Moderate correlation between ultrasonographic and histological thickness was computed for melanocytic skin tumors as well as for basal cell carcinomas (r=0.564 and r=0.690).

CONCLUSIONS

Medium frequency ultrasound is not a reliable tool for the precise measurement of thin (≤1mm) skin tumors. Ultrasonography using a 14-MHz frequency transducer enables more precisely to measure the thickness of basal cell carcinoma than melanocytic skin tumors. The 14-MHz ultrasound is support tool to suggest the morphologic type of skin tumor.

Ultrasound skin imaging

The interaction of high-frequency ultrasound waves with the skin provides the basis for noninvasive, fast, and accessible diagnostic imaging. This tool is increasingly used in skin cancer and inflammatory conditions as well as in cosmetic dermatology. This article reviews the basic principles of skin ultrasound and its applications in the different areas of dermatology.

Preoperative 15-MHz ultrasound assessment of tumor thickness in malignant melanoma

BACKGROUND

Tumor thickness is of great importance in the management of cutaneous malignant melanoma (MM): this variable not only affects prognosis but is also a key factor in planning surgical margins and selecting candidates for sentinel node biopsy. Breslow depth is the standard histologic measure of thickness, but technological advances have provided imaging techniques such as cutaneous ultrasound that can potentially assess tumor thickness and enable prompt initiation of definitive treatment.

OBJECTIVES

a) To evaluate the utility of ultrasound assessment of tumor thickness in MM, and b) to analyze histologic variables that affect ultrasound assessments of thickness.

MATERIALS AND METHODS

Retrospective study of a consecutive series of 79 primary cutaneous MMs in which tumor thickness had been assessed by 15-MHz ultrasound before surgery. We gathered data from histology reports, studying Breslow depth and the presence of ulceration, regression, inflammatory infiltrate, and associated nevi. Correlation coefficients were calculated to evaluate the strength of association between Breslow depth and thickness assessed by ultrasound. We also calculated the sensitivity, specificity, and positive and negative predictive values of ultrasound measurement in the diagnosis of MMs more than 1mm thick. Associations between histologic variables and the overestimation of thickness by ultrasound were also analyzed.

RESULTS

The 79 primary MMs studied had a mean (SD) Breslow depth of 0.8 (1.4) mm. There was moderate correlation and agreement between Breslow depth and the ultrasound assessment of thickness (Pearson correlation coefficient, 0.678; intraclass correlation coefficient, 0.78). The tendency of ultrasound to overestimate thickness was nonsignificantly related to the presence of a moderate to intense infiltrate and associated nevi (P>.05). The sensitivity of ultrasound for the diagnosis of MM over 1mm thick was 82%; specificity was 80%, and positive and negative predictive values were 54% and 94%, respectively.

CONCLUSIONS

Ultrasound imaging quite correctly identifies thin MMs and can be useful for planning adequate surgical margins; however, there are limitations on its usefulness in the diagnosis of thick MMs. Additional studies are required to confirm whether certain histologic characteristics, such as the presence of a moderate to intense inflammatory infiltrate or associated nevi can lead to overestimation of thickness by ultrasound, limiting the clinical utility of this imaging technique in MM management.

Sonography of the primary cutaneous melanoma: a review

The diagnosis and management of primary cutaneous melanoma have traditionally relied on clinical and histological characteristics. Nevertheless, in recent years there has been a significant growth in the usage of ultrasound for studying the cutaneous layers. Thus, the present paper focuses on the primary lesion, its sonographic characteristics, the potential benefits of early imaging, and the new developments on the ultrasound field applied to cutaneous melanoma.

Measurement of melanoma thickness--comparison of two methods: ultrasound versus morphology

OBJECTIVE

The aim of our study was to investigate the association between non-invasive ultrasound examination and morphologic test results in the measurement of cutaneous melanoma thickness influencing surgical treatment strategy.

METHODS

Our prospective clinical study has been conducted in the Clinic of Plastic and Reconstructive Surgery of Kaunas University of Medicine Hospital (KUMH) since January 2004 until October 2008. A total of 100 patients with a clear clinical diagnosis of stage I-II cutaneous melanoma were enrolled in this study. Melanoma depth was measured using a linear 14-MHz frequency ultrasound sensor (Toshiba Xario XG). Surgically removed fragments of skin-subcutaneous tissue were fixated using 10% formalin solution in the operating theatre, and sent to KUMH Clinic of Pathological Anatomy. The most informative sections were analysed for tumour thickness, according to Breslow, as well as tumour type, vascular and lymphatic invasion and dissemination. A comparative data analysis of melanoma thickness measured by ultrasound (T) preoperatively and histologically estimated cutaneous melanoma (CM) thickness according to Breslow (pT) using the Bland-Altman method was performed.

RESULTS

Higher mean difference of melanoma thickness (60 μm) between T and pT measurements was found when tumour thickness matched pT1 and pT2 categories. In cases of CM depth exceeding 2mm, mean difference of measurements between CM thickness determined by ultrasound and histological examination was lower (30 μm). Data regression analysis showed that correlation between T and pT measurements was lower when CM was thinner (1-2 mm) (Pearson's correlation coefficient, r: 0.283). In cases of thicker melanoma (>2 mm), strong and statistically significant (p<0.0001) correlation (r: 0.869) was observed.

CONCLUSIONS

Correlation between melanoma thickness measured using a linear 14-MHz frequency ultrasound sensor and histologically estimated melanoma thickness according to Breslow was lower if melanoma was thinner (1-2 mm). However, in cases of thicker melanoma (>2 mm), very strong correlation between measurements was observed.

Principles of high-frequency ultrasonography for investigation of skin pathology

Ultrasonography is a valuable diagnostic tool widely used in medicine. During the last three decades, this non-invasive skin imaging method has been extended to dermatology. High-frequency ultrasonography with higher than 20MHz scanners is well-established for measuring tumour thickness and skin thickness when treating inflammatory skin diseases such as scleroderma or psoriasis. High-frequency ultrasonography has become extremely helpful for the preoperative assessment of skin melanoma. The correlation between ultrasonic and histological measurements of melanomas thickness is significantly similarly good using transducers of 20, 75 or 100MHz frequency (r range from 0.895 to 0.99) and better compared with transducers of 7.5MHz frequency (r=0.76). The preoperative sonographically estimated thickness of skin melanoma is sometimes overestimated, because of an underlying inflammatory infiltrate and other reasons. Assessment of skin melanoma thickness using transducers of 100MHz frequency has better agreement with histology, compared with ultrasonography with 20MHz transducers. However, the ultrasonic penetration depth is limited to 1.5mm in case of 100MHz. The newer ultrasonic techniques such as high-frequency ultrasonography and colour Doppler sonography could be used for assessment of the tumour vascularization and its metastatic potential. The wide variety of diagnostic information provided by high-frequency ultrasonography undoubtedly improves the management of oncological and inflammatory skin conditions and underlines its essential position in dermatological practice.

High-resolution ultrasonography assists the differential diagnosis of blue naevi and cutaneous metastases of melanoma

BACKGROUND

Metastases of cutaneous melanoma may simulate benign blue naevi clinically.

OBJECTIVES

To investigate the value of ultrasonography in the differential diagnosis of lesions that look similar clinically, i.e. blue naevi and cutaneous metastases of melanoma.

METHODS

Participants were invited for inclusion in the study if they had a cutaneous blue lesion clinically suggestive of a blue naevus or cutaneous metastasis of melanoma. After obtaining signed consent, the lesion was photographed and studied using dermoscopy and high-resolution ultrasonography before being removed for histological examination. Clinical, dermoscopic and ultrasonographic images were reviewed anonymously by four dermatologists to assign the diagnosis of blue naevus or metastasis of melanoma. The diagnostic performance of clinical examination, dermoscopy and sonography was assessed for the ability of each to differentiate between metastases of melanoma and blue naevi with reference to the histological diagnosis. Moreover, experts undertook a semeiological description of each ultrasonographic image according to seven items: location of the lesion, echogenicity, homogeneity, shape of the lesion, definition of margins, posterior acoustic shadow and increased posterior echogenicity.

RESULTS

  Twenty-eight patients were included with a total of 39 blue skin lesions, and 17 of the 28 patients had a previous history of melanoma. Interobserver agreement in the semeiological description of the sonographic images was good (κ≥0·6) for five of seven items. Sonography was more specific (94%) than clinical examination (77%) and dermoscopy (74%). The sonographic features contributing to the differential diagnosis were: location of the lesion (P=0·027), shape of the lesion (P<0·001), homogeneity (P=0·001) and increased posterior echogenicity (P=0·007).

CONCLUSIONS

Ultrasonography is a reproducible and specific tool that can assist the differential diagnosis between blue naevi and metastases of melanoma. A blue naevus is a homogeneous, hypoechoic, 'dish-shaped' lesion, located in the superficial dermis, whereas metastases of melanoma are 'potato-shaped', hypoechoic, heterogeneous lesions, located in the hypodermis.

Pre-operative ultrasound with a 12-15 MHz linear probe reliably differentiates between melanoma thicker and thinner than 1 mm

BACKGROUND

Pre-operative determination of primary melanoma thickness could be a tool to identify those patients who could be treated with radical primary tumour excision and sentinel lymph node biopsy in a single procedure. An excellent correlation between sonographic and histological measurement of maximal tumour thickness has been achieved using 20-MHz transducers.

OBJECTIVE

To show that widely available high resolution ultrasound with 12-15 MHz linear probe could also reliably assess the thickness of primary melanoma.

METHODS

Sixty-nine patients underwent ultrasound evaluation of 70 clinically and dermoscopically suspicious pigmented skin lesions before surgical excision.

RESULTS

The sensitivity, specificity, positive and negative predictive values of ultrasound to detect melanoma > 1 mm were 92%, 92%, 95% and 81% respectively. The correlation between ultrasound and histological tumour thickness was very good [Pearson's correlating index 0.823 (P < 0.001)]. Mean difference between sonographic and histological measurements was 0.045 mm with limits of agreement estimated at -1.4 and +1.49, and a bias between two methods 45 microm.

CONCLUSION

Ultrasound examination with a 12-15 MHz linear transducer can reliably differentiate primary melanoma > 1 mm from those <or= 1 mm.

Preoperative assessment of cutaneous melanoma thickness using 10-MHz sonography

OBJECTIVE

The purpose of this study was to evaluate the prognostic value of 10-MHz sonography in measuring melanoma thickness before biopsy or excision.

SUBJECTS AND METHODS

Fifty-four patients with lesions suggestive of melanoma participated in the study. Lesions were measured on sonography using a 10-MHz linear transducer before routine biopsy and histopathologic analysis. Sonographic measurements were compared with histopathologic results (Breslow index) using Pearson's correlation coefficient and concordance analysis. Additional statistical analyses included sensitivity, specificity, accuracy, positive predictive value, and negative predictive value of 10-MHz sonography in identifying lesions > 1 mm thick.

RESULTS

Histopathologic analysis identified all 54 lesions as melanoma. On sonography, 34 lesions measured < or = 1 mm and 20 lesions, > 1 mm. Histopathologic analysis showed 32 lesions with a Breslow index of < or = 1 mm and 22 lesions with a Breslow index of > 1 mm. The median thickness of the 54 lesions was 1.33 mm (range, 0-5 mm) by the Breslow index compared with 1.85 mm (range, 0-4.8 mm) by sonography. Comparison of sonographic measurements and Breslow index values gave a correlation coefficient of 0.93 and a concordance coefficient of 0.99. Overall, sonographic measurements showed 86% sensitivity, 97% specificity, 93% accuracy, 95% positive predictive value, and 91% negative predictive value in identifying lesions with a Breslow index of > 1 mm.

CONCLUSION

In our series of 54 melanomas, 10-MHz sonography measured lesion thickness with good accuracy compared with histopathology. Sonography was effective in discriminating between tumors < or = 1 mm thick and those > 1 mm thick.

Preoperative measurement of thickness of cutaneous melanoma using high-resolution 20 MHz ultrasound imaging: A monocenter prospective study and systematic review of the literature

Histologic measurement of the thickness of melanoma is a major prognostic factor and governs the size of the surgical excision (1cm for melanomas less than 1 mm thick, 2 cm for melanomas thicker than 2 mm and 3 cm beyond 4 mm). To determine whether high-resolution ultrasound can be used to predict surgical margins and, thus, to operate on patients in a single procedure avoiding further re-excision, we performed a systematic review of studies published from January 1987 to June 2007 and a prospective study. The systematic review selected 14 studies comparing histologic and ultrasound measurements and showing correlation coefficients generally greater than 0.9. Data available from 7 of the 14 studies (total 869 patients) showed predictive values of adequate margins in at least 72% of lesions using preoperative measurement of ultrasound thickness. The prospective study included 31 patients referred with a primary melanoma from March 2005 to March 2007. Ultrasound measurement of thickness was possible except for thin melanomas (<0.4 mm) in areas with marked photoaging, in the plantar zone, and in the case of very thick melanomas exceeding the explored depth (7.6 mm). The average thickness was 1.96 mm measured by ultrasound (SD: 2.15) and 1.95 mm by histology (SD: 2.62) and the Bland and Altman graph showed moderate agreement between ultrasound and histology. Limits of agreement were estimated at -1.4 and +1.8, corresponding to relative limits of agreement of -40 to +80%. Ultrasound predicted appropriate margins (1, 2 or 3 cm wide according to sonometric thickness) in 26 of the 31 subjects (84%, 95% CI 66-95). Preoperative high-resolution ultrasound is a noninvasive examination that can help in choosing appropriate surgical margins and should reduce the need of partial or excisional biopsy before surgery, and the need for further re-excision.

Preoperative Ultrasonic Assessment of Thin Melanocytic Skin Lesions Using a 100-MHz Ultrasound Transducer: A Comparative Study

BACKGROUND

It has been shown that tumor thickness (TT) of melanocytic skin lesions (MSL) of less than 1 mm vertical thickness assessed by 20 MHz are often incorrectly evaluated.

OBJECTIVE

We aimed to evaluate the accuracy of 100-MHz ultrasound for the determination of TT of thin MSL, compared with conventional 20-MHz ultrasound and histologic findings.

METHODS

Thirty-seven patients with 50 suspicious MSL, including tumor diameter up to 1 cm and maximum vertical TT of less than 1 mm, were recruited. The agreement between the histologically and ultrasographically measured TT was analyzed using Bland and Altman plots.

RESULTS

Compared to histology, 20-MHz ultrasound (33.9 microm) as well as 100-MHz (16 microm) resulted in overestimation of TT that was twofold higher for 20-MHz ultrasound. The latter also revealed wider 95% limits of agreement (4.9 to 63 microm) than 100-MHz ultrasound (3.5 to 28.7 microm).

CONCLUSION

Analysis of agreement clearly demonstrated that the performance of 100-MHz ultrasound is superior to conventional 20-MHz ultrasound, even though a relatively small positive bias was observed in 100-MHz ultrasound, indicating a systematic error. We consider 100-MHz ultrasound a useful tool for the noninvasive determination of TT of thin MSL in vivo.

Prognostic value of angiogenesis evaluated with high-frequency and colour Doppler sonography for preoperative assessment of primary cutaneous melanomas: correlation with recurrence after a 5 year follow-up period

OBJECTIVE

To study the value of high-frequency sonography (HFS) and colour Doppler sonography (CDS) in evaluating the 5 year metastatic potential of primary cutaneous melanomas (CM).

MATERIALS AND METHODS

111 CM were studied before surgical resection and 107 were depicted on HFS. The maximal HFS thickness was measured and compared with the Breslow thickness. A CDS study was performed in each tumour.

RESULTS

HFS thickness ranged from 0.26 to 8.0 mm and Breslow thickness from 0.15 to 8.0 mm. HFS and Breslow thickness correlated strongly (r > 0.93). Intratumour vessels were depicted in 43 of the 107 CM, of which 40 were thicker than 2 mm. The median follow-up was 61 months and 27 patients developed relapses. In the univariate analyses, neovascularization visualized with CDS, sonographic thickness and the Breslow thickness were significantly linked to relapses (p < 0.0001), as were lymph node status and ulceration (p = 0.007 and 0.004).

CONCLUSION

Vascularization was observed mainly in thick primary melanoma. A median follow-up of 5 years showed the prognostic value of angiogenesis evaluated by CDS.

Noninvasive Imaging of Skin Tumors

In this article, the authors review different approaches to the diagnosis of skin tumors using noninvasive diagnostic tools, which are becoming increasingly reliable and, as a consequence, increasingly popular among physicians and patients. Especially in the realm of pigmented skin lesions, dermoscopy and sonography may add useful information to the clinical constellation, improving the diagnostic performance for early diagnosis of melanoma and for differentiating various melanocytic and nonmelanocytic pigmented lesions. More recently, confocal scanning laser microscopy was introduced as a novel technique that enables the in vivo study of the skin at a nearly histologic resolution, being of diagnostic value in various skin disorders, including basal cell carcinoma and pigmented skin lesions. These modalities have various other potential applications besides diagnosis, including lesion's selection for biopsy, determination of appropriate therapeutic modalities, verification of treatment efficacy, and decision of surgical margins. Finally, a hint to the use of cytodiagnosis for basal cell carcinoma is provided.

Reproducibility of repeated measurements on post-burn scars with Dermascan C

The present study investigated the reproducibility of measurements with the Dermascan C on post-burn scars. Intra- and inter-rater reproducibility and test-retest reliability with a one week time lapse were examined on 40 post-burn scars of 6 volunteering burn patients by means of intra-class- correlation coefficients (ICC) and standard error of measurements (SEM). Results showed good to excellent values for ICC in all the three conditions. On the basis of these results, we concluded that the instrument provides reliable information and can be used in comparative clinical trials that examine therapeutic strategies on healing scars.

Computer-aided melanoma diagnosis

This article presents a snapshot of fast-moving research into the application of digital imaging technology to in vivo computer-aided diagnosis of early melanoma. It is written from the perspective of a researcher with a keen interest in bringing this technology to physicians' offices. The primary emphasis is on reviewing the existing literature, supplemented by unpublished material relating to a particular system and as yet unpublished research studies.

High frequency ultrasound in the preoperative staging of primary melanoma: a statistical analysis

High frequency sonography has been shown to be a useful tool in the preoperative staging of malignant melanoma. In the present study sonometric and histometric data concerning tumour thickness were compared, using appropriate statistical methods, in order to assess the accuracy of ultrasonography. From December 1997 all pigmented lesions suspected of being melanoma were preoperatively assessed by a 20 MHz ultrasound B scan. The results of these ultrasound examinations were compared with histometric data. Pearson's correlation coefficient and absolute and relative differences were used for statistical analysis. Of the 261 examined lesions, 193 were malignant melanoma. A high correlation between sonometry and histometry was computed (r = 0.95), with an absolute difference of 0.32 +/- 0.03 mm (mean +/- SEM) and a mean relative difference of 27.2% (95% confidence interval 23-31.4%). The highest correlation was found in melanoma > or = 1.51 mm thick and the lowest correlation in melanoma < or = 0.75 mm. In conclusion, the high accuracy of this technique in the preoperative staging of malignant melanoma would offer a basis for defining the surgical margins of > or = 0.76 mm thick lesions. The limited accuracy of sonometry in the preoperative staging of thin melanoma < or = 0.75 mm has emerged by applying adequate statistical methods.

The velocity of ultrasound in human primary melanoma tissue - implications for the clinical use of high resolution sonography

BACKGROUND

Ultrasonography with 20 MHz frequency can be used to estimate tumour thickness preoperatively in malignant melanoma (MM) of the skin. The vertical invasion depth is the single most important prognostic factor for localised MM, and its preoperative knowledge would be very useful for the planning of surgical procedures. Since ultrasonographic distance measurements directly depend upon the tissue specific ultrasound velocity, we determined the ultrasound velocity in primary melanoma.

RESULTS

Ultrasound velocity was calculated from runtime differences of a 20 MHz ultrasound signal along a known distance either through water alone or through thick specimens of primary MM. The ultrasound velocities varied between 1553 m/s and 1588 m/s with a mean of 1564 m/s in four different MM specimens. The analysis of different parts of the specimens showed that the variation of the calculated velocities was larger between different specimens than within one individual specimen.

CONCLUSIONS

The ultrasound velocity in MM tissue may be slightly lower than normally assumed, thereby explaining a part of the overestimation usually found in sonographic measurement of melanoma invasion depth. Additionally, the variation of ultrasound velocity between individual tumours may contribute to the impairment of the correlation found between sonometry and Breslow's measurement of MM invasion depth. For practical reasons, a setting of 1580 m/s will be appropriate for ultrasonography of primary malignant melanoma.

Non-invasive analysis of melanoma thickness by means of dermoscopy: a retrospective study

Epiluminescence microscopy (ELM), or dermatoscopy, is a non-invasive technique for the diagnosis of cutaneous melanoma that may play a role in the non-invasive, preoperative assessment of melanoma thickness. This study investigated the correlation between the frequency of appearance of some standard ELM criteria and the histological thickness of melanomas. In addition, the possible role of the total dermoscopic score (TDS) according to ABCD rule of dermoscopy as a predictor of melanoma thickness was analysed. The dermoscopic images of 84 cutaneous melanomas were retrospectively investigated to evaluate the presence of 10 standard ELM criteria, and for each lesion the TDS was established (with observers blinded as to the tumour thickness). A statistically significant association was found between the presence of an irregular pigment network and melanomas with a Breslow index equal to or lower than 0.75 mm (positive predictive value of 68%); in contrast, radial streaming, atypical vascular pattern and grey-blue areas were associated with melanomas > 0.75 mm (positive predictive values of 77%, 65% and 70%, respectively). Of the melanomas thinner than 0.76 mm, 82% showed a TDS lower than 6.80 (optimized cut-off point), while 79% of melanomas thicker than 0.75 mm had a TDS higher than 6.80 (chi2 = 30.815, P < 0.001); the positive predictive value of a TDS > 6.80 in the detection of lesions thicker than 0.75 mm was 79%. In conclusion, a statistically significant correlation does exist between some dermoscopic features and melanoma thickness. Both the mostly used dermoscopic methods (standard ELM pattern analysis and the ABCD rule of dermatoscopy) may provide useful information in the non-invasive assessment of melanoma thickness. However, their diagnostic performance is far from 100%; further studies are needed to investigate whether the combination of dermoscopy with other non-invasive approaches (e.g. sonometry) may result in an overall improvement in the diagnostic performance.

Preoperative assessment of melanoma thickness by ABCD score of dermatoscopy

BACKGROUND

Epiluminescence microscopy is a useful tool for the noninvasive diagnosis of malignant melanoma based on criteria that have been correlated with specific histologic characteristics. Previous studies have also shown a good correlation between the frequency of some dermatoscopic criteria based on pattern analysis (pigment network, blue-gray areas, vascular pattern) and tumor thickness. This technique could be useful in the preoperative assessment of tumor thickness as an indication for sentinel node biopsy.

OBJECTIVE

Our purpose was to evaluate the possible role of the total dermatoscopy score (TDS) assigned to a series of lesions in accordance with the ABCD rule of dermatoscopy as a preoperative predictor of melanoma thickness.

METHODS

For 84 cutaneous melanomas (17 were in situ melanomas; 67 invasive cases with mean thickness 0. 93 mm; range, 0.2-3.9 mm; standard deviation, 0.63) consecutively excised at the Department of Dermatology of Florence, TDS was established by two observers blinded as to the tumor thickness. The performance of different cut-off points of TDS in the diagnosis of melanoma with Breslow's thickness more than 0.75 or 1.00 mm was investigated by receiver operating characteristic (ROC) analysis. Accuracy of classification was evaluated in terms of sensitivity, specificity, and area under ROC curves (AUC).

RESULTS

The TDS assigned to cutaneous melanomas by the ABCD rule increased with the thickness of the lesions from in situ melanomas to melanomas of intermediate thickness (0.75-1.50 mm). As a preoperative method for the detection of melanomas with a Breslow thickness greater than 0. 75 mm, a TDS cut-off point of 6.80 showed 80% sensitivity, 84% specificity, and 82% diagnostic accuracy (AUC value, 0.90). TDS performed better in the diagnosis of a thickness threshold of 0.75 than 1.00 mm (higher AUC value).

CONCLUSION

The TDS calculated by the ABCD rule of dermatoscopy-a simplified approach to dermatoscopic diagnosis of melanoma-provides useful information for the preoperative assessment of melanoma thickness greater than 0.75 mm.

Dermatoscopy and high frequency sonography: two useful non-invasive methods to increase preoperative diagnostic accuracy in pigmented skin lesions

Dermatoscopy and high frequency sonography have recently been combined to increase diagnostic preoperative accuracy in the treatment of pigmented skin lesions. In this monocentric study 80 patients with pigmented skin lesions were evaluated clinically, by dermatoscopy, and 20 MHz-sonography followed by dermatohistopathological evaluation; 39 malignant melanomas, 37 common nevi, 3 dysplastic nevi, and 1 nevus Spitz were diagnosed histologically. In 72 of the 80 cases (91.3%) dermatoscopical diagnoses were confirmed by histopathology, compared to only 79% correct clinical diagnoses. For the mere clinical diagnosis of melanoma sensitivity was 79%, specificity was 78% and diagnostic accuracy was 65%. All diagnostic values increased by dermatoscopy: sensitivity reached 90%, specificity was 93%, and diagnostic accuracy was 83%. In order to determine tumor thickness preoperatively tumor thickness was measured by 20 MHz sonography. The correlation of tumor thickness between histometric and sonographic results was determined for nevi (r = 0.93) and melanoma (r = 0.95); 74.3% of melanomas were diagnosed correctly within an 0.2 mm range. Regarding the clinical important limit of 1 mm tumor thickness, 87.2% were diagnosed in accordance with histometric evaluation. An increase of 18% in diagnostic accuracy by dermatoscopy and 87.2% of correctly diagnosed cases of tumor thickness of malignant melanoma by high frequency sonography clearly demonstrate that these methods should be considered standard procedures in the diagnosis of pigmented skin lesions and will facilitate the decision on necessary surgical treatment.

Ultrasound-guided thermocouple placement for cryosurgery

BACKGROUND

Although cryosurgical methods have high cure rates, imprecise estimates of both skin lesion depth and destructive temperature front location result in subjective technique in skin malignancy treatments.

OBJECTIVE

We evaluated the possibility of newer ultrasound equipment to assist in the precise placement of thermocouples in human skin.

METHODS

DermaScan C ver. 3 ultrasonographic equipment fitted with a sharp focus probe with a frequency of 20 MHz and a scan length of 12.1 mm was used to locate thermocouples with 27- and 30-gauge needles.

RESULTS

We successfully and reproducibly located thermocouples and thin needles, and accurately measured their distance from the skin surface.

CONCLUSION

Ultrasound is a useful method for the accurate placement of thermocouples, and needles as thin as 30 gauge for monitoring in cryosurgery.