Ultrasound in dermatology. Part II. Ultrasound of regional lymph node basins and subcutaneous tumours.
Ultrasound in dermatology is a non-invasive tool for the detection and verification of tumours in skin, subcutaneous tissues and in lymph node basins. Since the introduction of ultrasound examination in the routine practice of dermatology in the late seventies [1], ultrasound has evolved to become a standard diagnostic method, at least in Europe. Subcutaneous or regional nodal metastases or benign tumours or tissue accumulation may not be palpable due to small size, distance from the skin surface or location in an area of postoperative or radiation fibrosis, which renders a physical examination on its own difficult. Palpation even by an experienced physician is also known to be an inaccurate technique for the assessment of lesions in head and neck cancer [2] as well as in scar tissue. Ultrasound, on the contrary is able to give additional and reliable information about the exact position of a tumour, surrounding anatomical structures, the dimension of the lesion in two perpendicular diameters in mm, its echo pattern as well as the distance from the skin surface. High resolution ultrasound technique is not only able to detect small targets (< 3 mm), but also to predict difficulties in the surgical search for metastases due to a deep subcutaneous or intramuscular position, or a localization near structures (e.g. vessels) which could easily be traumatized. Several invasive and non-invasive staging tools have been developed for the detection of regional disease or tumours in the soft tissue to support the often ineffective physical examination on its own. Among these techniques, ultrasound has been proven to have superior sensitivity to physical examination in the detection of regional metastases in melanoma patients [3-6] as well as in hematology and oncology patients [7] and it even facilitates the surgical management of such patients [8-10]. Based on technical equipment and clinical requirements, ultrasound used in dermatology is performed using frequencies between 7.5 and 15 MHz. Additionally duplex and colour flow analysis may complement grey-scale ultrasound by demonstrating tumour vascularity and characterising masses [11, 12]. In this part of the two CME articles on ultrasound we want to illustrate the most important technical details, procedural steps and the clinical use of high-frequency ultrasound in dermatology.
Ulrich
J
J
Department of Dermatology, Otto von Guericke University, 39120 Magdeburg, Germany. jens.ulrich@medizin.uni-magdeburg.de
Voit
C
C
D006801:Humans; D008207:Lymphatic Metastasis / Q000000981:diagnostic imaging; D012878:Skin Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology*; D014463:Ultrasonography