Contrast-Enhanced Ultrasound for Characterizing Lymph Nodes With Focal Cortical Thickening in Patients With Cutaneous Melanoma

OBJECTIVE: The aim of this study was to ascertain the utility of contrast-enhanced ultrasound in assessing the significance of focal cortical thickening in the lymph nodes of patients followed up after surgery for cutaneous melanoma. MATERIALS AND METHODS: Ultrasound was used to examine 460 consecutive patients to identify nodes with focal hypoechoic cortical thickening. Patients whose nodes revealed these features underwent contrast-enhanced ultrasound and ultrasound-guided fine-needle aspiration cytology (FNAC) focusing on the area of cortical thickening. Enhancement in the arterial and parenchymal phases was evaluated: A generalized homogeneous or intense enhancement was considered benign and the presence of a perfusion defect was considered metastatic. RESULTS: After exclusion of 24 patients with frank signs of malignancy at gray-scale ultrasound, the study included 436 patients. Focal hypoechoic cortical thickening was seen in 44 of 436 nodes in as many patients. In 29 nodes, the area of focal thickening showed contrast enhancement similar to that of the remaining cortex on contrast-enhanced ultrasound. In 15 nodes, the area of cortical thickening was less well vascularized than the adjacent parenchyma in the arterial phase and there were areas with perfusion defects that were more evident in the parenchymal phase. FNAC focusing on the areas of focal cortical thickening identified 13 metastatic nodes and 31 nodes with benign features. Contrast-enhanced ultrasound compared with FNAC correctly classified 42 of 44 nodes, showing a sensitivity of 100% and a specificity of 99.5%. CONCLUSION: Although our findings need to be confirmed in larger series, they indicate that contrast-enhanced ultrasound can be useful in clinical practice for characterizing focal cortical thickening in lymph nodes. The exclusion or identification of regional lymph node metastases is of fundamental importance in oncologic staging because this issue directly influences both the prognosis and the choice of therapeutic strategy.