Objective: The purpose of this study was to describe the sonographic appearances of melanoma metastases of the skin, subcutaneous tissues, and superficial lymph nodes.
Materials and methods: Gray-scale sonography was performed on 31 superficial melanoma metastases in 18 patients. Discreteness of borders, contours, echogenicity, echotexture, and degree of acoustic through-transmission were evaluated for each lesion. Color Doppler sonography was also performed on 25 of the 31 lesions, by which the amount of internal color flow was qualitatively assessed.
Results: Twenty-eight (90%) of the 31 metastases had well-defined borders. Contours were smooth in 17 (55%), lobulated in 12 (39%), and spiculated in two (6%). Nineteen metastases (61%) were hypoechoic to muscle, 10 (32%) were isoechoic, and two (6%) were hyperechoic. Echotexture was homogeneous in six lesions (19%), mildly heterogeneous in 13 (42%), moderately heterogeneous in 11 (35%), and markedly heterogeneous in one (3%). Twenty-two lesions (71%) showed enhanced acoustic through-transmission. Of the 25 melanoma metastases for which we performed color Doppler sonography, 18 (72%) had internal arterial color flow and seven (28%) did not. The flow was characterized as mild in 13 (72%) of 18, moderate in four (22%), and marked in one (6%).
Conclusion: On sonography, superficial melanoma metastases typically are well-defined hypoechoic lesions with smooth or lobulated contours, mild to moderate heterogeneity, and enhanced acoustic through-transmission. Internal flow revealed by color Doppler sonography is present in many, but not all, superficial melanoma metastases.