Role of High-Resolution Ultrasound and PET/CT Imaging for Preoperative Characterization of Sentinel Lymph Nodes in Cutaneous Melanoma

The purpose of our study was the comparison of high-resolution ultrasound (HRUS) and positron emission tomography combined with computerised tomography (PET/CT) in the preoperative characterization and identification of subclinical nodal metastases focusing on sentinel lymph nodes (SLN) in melanoma patients. Patients with cutaneous melanoma (CM) who received sentinel lymph node biopsy at the Department of Dermatology and Allergy, University of Bonn, between January 2009 and January 2011 had been evaluated with a retrospective computer-aided search concerning preoperative staging procedures. A combination of PET/CT and HRUS had been performed preoperatively in 20 of 123 patients. A total of 59 SLNs had been removed in those 20 patients followed by histopathologic examination. HRUS correctly identified two of 17 positive SLNs whereas PET/CT imaging identified none. The sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of HRUS were 11.8 % (95 % confidence interval [CI] = 3.3-34.3), 100 % (95 % CI = 91.6-100.0), 100.0 % (95 % CI = 34.2-100.0), and 73.7 % (95 % CI = 61.0-83.3), respectively. On the basis of this limited study cohort, HRUS had a better value than PET/CT in preoperative identification of positive SLNs, suggesting a possible diagnostic superiority of HRUS in general characterization of peripheral nodal disease in CM.