Duan Li MD, Presenter: Nothing to Disclose

Ariadne Maria Bach MD, Abstract Co-Author: Nothing to Disclose

Michael Joseph Sohn, Abstract Co-Author: Nothing to Disclose

Detecting metastatic lymph nodes from primary malignant melanoma is of clinic significance in staging and follow-up evaluation. This study was performed to evaluate the accuracy of ultrasound in the detection of melanoma nodal metastasis

A retrospective analysis of prospectively collected data from a tertiary cancer center was performed. Total of 157 consecutive patients with melanoma who had preoperative or pre-biopsy ultrasound evaluation of lymph nodes between 2/1/2008 and 3/10/2011 were included. All ultrasound exams were correlated with either cytology or surgical pathology results. The following ultrasound features were assessed: Nodal size, shape, border, echogenicity of cortex, presence of central hilus, vascular pattern of the lymph nodes. Diagnostic accuracy of each ultrasound feature was calculated.

Sixty-three patients proved to have metastatic lymph nodes and 94 patients proved to have benign lymph nodes. The benign lymph nodes included reactive change and granulomatous inflammation. The location of the lymph nodes included neck, supraclavicular, axillary,  inguinal regions, as well as within abdominal and chest wall subcutaneous tissue. The size of the lymph nodes ranged from 5 mm to 5.1 cm. Multivariate analysis was performed using 1) rounded shape: longitudinal-transverse diameter ratio <2, 2).heterogenous change of cortex with hypoechoic foci, 3) loss of fatty hilum, 4) displacement of central hilum, 5) presence of peripheral vascularity or mixed vascularity, and 6) presence of peripheral vascularity and loss of fatty hilum or displacement of central hilum. The diagnostic accuracy of each ultrasound findings in this study varies widely. Most ultrasound features had high specificity, ranging from 72% to 96%, but low sensitivity, ranging from 21% to 75%. Presence of peripheral vascularity combined with loss of fatty hilum is the most sensitive feature in detecting metastatic lymph node. Presence of hypoechoic foci within the cortex ( as small as 4 mm) of the lymph nodes provides the highest sensitivity in detecting micrometastasis.

Sonographic characteristics of lymph nodes have significant diagnostic value in differentiating metastatic lymph nodes from benign lymph nodes in patients with melanoma

The ultrasound characteristics of lymph nodes have significant diagnostic value in differentiating and staging metastatic melanoma.

Li, D, Bach, A, Sohn, M, Sonographic Features of Nodal Metastasis from Melanoma Play a Major Role in Detecting Early Melanoma Metastasis.  Radiological Society of North America 2011 Scientific Assembly and Annual Meeting, November 26 - December 2, 2011 ,Chicago IL. http://archive.rsna.org/2011/11012274.html