The intricacy of the head and neck lymphatic system translates to several technical challenges for preoperative lymphoscintigraphy. 1) ( 6) therefore, melanoma of the head and neck is one of the most difficult tumors for which to predict the lymphatic drainage pathway. The head and neck region contains a network of more than 350 lymph nodes in an exceptionally compressed area ( Fig. In patients with cutaneous melanomas of the head and neck, preoperative lymphoscintigraphy is challenging because of the complexity of the lymphatic drainage system in this region. The estimated number of new cases of cutaneous melanoma in 2006 is 62,190, and the estimated number of deaths is 7,910 ( 9). The survival rate for stage III melanoma at diagnosis is approximately 10% ( 8). If a sentinel node is positive for melanoma metastasis, then the disease is stage III, which has a 20% 10-y survival rate the survival rates are 85% for stage I and 60% for stage II ( 7). This information, in turn, helps the surgeon to minimize the size of the incision ( 6). Preoperative lymphoscintigraphy can contribute to nodal staging by revealing lymphatic drainage patterns and the locations of single or multiple sentinel lymph nodes at a specific ipsilateral, bilateral, or contralateral location relative to the primary tumor site. Melanoma is staged with the TNM system, in which T represents tumor thickness and ulceration, N represents spread to lymph nodes, and M represents metastasis to distant organs ( 5). In the Breslow system, thickness is measured with an ocular micrometer to determine the maximum vertical thickness (<0.76 mm for stage I, 1.5–4.0 mm for stage II, and metastasis for stage III) ( 1– 4). Tumor thickness is the single most important prognostic factor. In patients with a histopathologic diagnosis of cutaneous melanoma, the tumor must be staged to determine prognosis and treatment. Malignant melanoma should be suspected when any pigmented skin or mucosal surface lesion changes in color or size or begins to itch or bleed. Early melanoma is highly curable, but once the disease becomes disseminated, it is nearly always fatal. After reading this article, the reader should understand the lymph node level classification system for head and neck melanomas, be able to describe the technique used for the imaging of sentinel nodes in the head and neck region, and be able to demonstrate how SPECT/CT lymphoscintigraphic imaging can enable precise sentinel node localization and thus help to ensure minimal dissection.Ĭutaneous malignant melanoma is a relatively common tumor. Hybrid SPECT/CT lymphoscintigraphic imaging facilitates the localization of sentinel nodes by reliably showing the relationships between sentinel nodes and important anatomic structures. However, technical problems often render marker images of little or no use. In patients undergoing standard lymphoscintigraphy, obtaining lateral marker images that show important anatomic landmarks can help with the localization of sentinel nodes. Lymph nodes in the head and neck are grouped into 7 regions, or levels, on the basis of anatomic landmarks. However, it is very difficult to determine the exact locations of head and neck sentinel nodes on preoperative lymphoscintigraphy without the use of anatomic landmarks. In patients with head and neck tumors, preoperative lymphoscintigraphy can be used to map lymphatic drainage patterns and identify sentinel lymph nodes.
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