Ultrasonographic evaluation of superficial lymph node metastases in melanoma

The aims of the present work were to assess the diagnostic accuracy of ultrasonographic evaluation of superficial lymph nodes in patients with cutaneous melanoma and to describe the sonographic characteristics which permit early detection of neoplastic nodal involvement. Eighty-seven patients (89 lymph node sites) were studied for approximately a 3-year period, with a minimal surveillance time of 1 year. The ultrasonographic imaging equipment utilized were a 10 MHz scanner with a mechanical and one with 10 MHz electronic linear probe. The characteristics considered indicative of possible metastatic involvement were: round shape (short to long axis ratio > 0.5), no central hilus, nodular areas within the lymph node, sinuosity of the lymph node edges and lymph node with regular morphology and echostructure but with maximum diameter greater than 3 cm. Generally inguinal and axillary lymph nodes are larger than cervical ones. Of the 89 sites explored, 32 were considered 'suspect'. All 32 of these were subjected to cytology using ultrasound-guided, fine needle aspiration. The remaining 56 came in for a periodic control examination during a year. Thirteen of the 32 'suspect' lymph nodes proved positive at the pathologic examination. Two patients whose ultrasound diagnosis was negative developed metastases within 2 to 4 months (ultrasound false negatives). Our study indicates that there are sonographic features indicative of lymph node metastases from melanoma even in the early stages of the disease. Ultrasound scanning, therefore, is a useful diagnostic tool in the follow-up of melanoma patients, identifying which should be subjected to further testing with needle biopsy.