Ultrasound Morphology Criteria Predict Metastatic Disease of the Sentinel Nodes in Patients With Melanoma

Abstract

PURPOSE We have shown that ultrasound (US) -guided fine needle aspiration cytology (FNAC) can accurately identify the sentinel node (SN). Moreover, US-guided FNAC before the surgical SN procedure could identify up to 65% of all SN metastases. Herein we analyzed in detail the different US morphologic patterns of SN metastases. PATIENTS AND METHODS From July 2001 to December 2007, a total of 650 patients with melanoma scheduled for sentinel lymph node dissection were examined. We present the first 400 with sufficient follow-up (mean 40, median 39 months). Several morphologic characteristics were scored. In case of suspicious/clearly malignant US patterns a FNAC was performed. The final histology was considered the gold standard. Results Median Breslow was 1.8 mm. The sensitivity and positive predictive value of the most important factors were: peripheral perfusion (PP) present (77% and 52%, respectively), loss of central echoes (LCE; 60% and 65% respectively), and balloon shape (BS; 30% and 96% respectively). Together these factors have a sensitivity of 82% and PPV of 52% (P < .001). PP identified more patients with lower volume disease. PP and combined BS and LCE were independent prognostic factors for survival (hazard ratio, 2.19; P < .015; and hazard ratio, 5.50; P < .001, respectively). CONCLUSION Preoperative US and FNAC can identify 65% of SN metastases and thus reduce the need for surgical SN procedures. Peripheral perfusion is an early sign of involvement and of crucial importance to achieve a high identification rate. Balloon shape and loss of central echoes are late signs of metastases. We recommend US evaluation to identify those patients, who can directly proceed to a complete lymph node dissection after a positive US-guided FNAC of the SN.

Malignant Melanoma S3‐Guideline “Diagnosis, Therapy and Follow‐up of Melanoma”

“…Numerous studies have been conducted evaluating sonography in melanoma patients. The following criteria suggest malignancy: 1: ballooned shape; 2: loss of central echoes; 3: detectable peripheral perfusion [114]. A total of 6 642 patient were included in a meta-analysis by Bafounta et al [113] comprising 12 trials that assessed the validity of sonography, compared to mere palpation, in the evaluation of lymph node invasion in melanoma patients.…”

Contrast-Enhanced Ultrasound Imaging of Sentinel Lymph Nodes After Peritumoral Administration of Sonazoid in a Melanoma Tumor Animal Model

“…6 Diagnostic ultrasound imaging (US) has been used to evaluate lymph nodes (LNs) for both benign disease as well as metastases. [12][13][14] It has also been found to be a valuable method to guide LN biopsies. 15,16 Although gray scale US, color flow US, and pulsed Doppler imaging have been used alone or in combination to assess LNs for the presence of metastases, US cannot be used for lymphatic mapping (ie, to identify a tumor's SLNs) because mapping requires administration of a tracer (eg, dye or radiopharmaceutical).…”

“…[36][37][38][39][40][41] Conventional gray scale US features of metastatic involvement in LNs include enlargement, a round rather than oval shape (ie, size ratios), cortical thickness abnormalities, loss of the typical echogenic hilum, and abnormal vascular architecture. [12][13][14]38,41,42 Several published reports have described the sensitivity, specificity, and accuracy of US for LN metastases, primarily for breast applications. [12][13][14][15]38,41,42 In patients with breast cancer, the lymphatic drainage pathways are relatively predictable, whereas in patients who have melanoma, the location of the SLNs is more variable.…”

“…[12][13][14]38,41,42 Several published reports have described the sensitivity, specificity, and accuracy of US for LN metastases, primarily for breast applications. [12][13][14][15]38,41,42 In patients with breast cancer, the lymphatic drainage pathways are relatively predictable, whereas in patients who have melanoma, the location of the SLNs is more variable. 43,44 This project has confirmed the potential utility of lymphosonography as a lymphatic mapping technique and its ability to localize SLNs even in cases of unpredictable drainage pathways.…”

Optimal follow-up for melanoma

“…A few radiologists are in favor of staging regional lymph node basins in stage I-II melanoma with high-resolution ultrasonography [24][25][26]. However, the general opinion is that targeted high-resolution ultrasonography is not an effective substitute for SLNB in patients with primary melanoma [27][28][29][30].…”