The Journal of the Florida Medical Association最新文献

Contrary to the trend of early diagnosis observed in other parts of the world, in Florida melanoma is still being discovered in the more advanced stages. This is characterized by thicker lesions at diagnosis, which are hallmarked by bleeding, itching, ulceration, and increased vertical growth. In a study of 1,626 cutaneous melanoma patients at the H. Lee Moffitt Cancer Center in Florida, three prognostic factors, tumor thickness, Clark level, and presence of ulceration in the primary tumor, have remained relatively constant over an eight-year period (1987-1994). Despite the lack of change in tumor thickness in the last four years, mortality rate is decreasing, possibly due to more effective treatments. Regardless of these apparent improvements in mortality rates, definite progress must be made in the early detection of malignant melanoma through the initiation of statewide programs of lay public and professional education. In addition, it is proposed that the establishment of statewide screening programs of the Caucasian population with skin phenotypes 1 and 2 will also facilitate the early diagnosis of melanoma in the future, improve the outlook for these patients, and begin to address a major public health problem in the state of Florida.

Intra-operative sentinel lymph node (SLN) mapping and biopsy is a procedure that accurately stages the regional lymph node basin. Defined patterns of lymphatic drainage allow intra-operative determination of the first (sentinel) lymph node in the regional basin, and the absence of metastatic disease in the SLN accurately reflects the absence of melanoma in the remaining regional nodes. The use of a radiocolloid and a handheld gamma probe together with a vital blue dye provides optimal results, and allows for the successful identification of the SLN(s) in over 98 percent of the procedures. Close collaboration between surgeons, nuclear radiologists and pathologists is required to ensure optimal results. Surgical excision of the SLN allows for a more thorough and focused pathological examination of one or two nodes. Examination of serially sectioned SLNs by H&E staining, immunohistochemical staining and perhaps RT-PCR should reduce the number of patients with missed microscopic melanoma in the regional lymph nodes. Recently reported survival data from the Intergroup Melanoma Trial suggest that patients may benefit from identification and removal of regional lymph nodes that contain metastatic melanoma. Furthermore, the survival benefit recently reported in patients with melanoma metastatic to regional nodes prospectively randomized to receive high dose Interferon alfa-2b signals that the surgeons should aggressively examine patients for the presence of occult regional melanoma metastases. Intra-operative SLN mapping and SLN biopsy is a cost-effective procedure that allows accurate identification of regional lymph nodes that contain metastatic melanoma.

One of the most important prognostic indicators in patients with malignant melanoma is lymph node status. While the five-year survival of stage I and II patients (without clinical adenopathy) is approximately 80 percent, this drops to 36-50 percent in patients with clinical or microscopic lymph node involvement. Other factors within lymph node specimens which affect disease-free and overall survival are the number of positive nodes (1 vs. 1-3 vs. 4 or greater) and the presence of extracapsular extension. Recently, the technique of sentinel lymphadenectomy has been developed to facilitate detection of metastatic disease in regional lymph nodes. Successful completion of this procedure requires a specialized but multidisciplinary approach, utilizing the surgeon, oncologist, nuclear radiologist, and pathologist. The pathologist's role is pivotal in this process, because identification of melanoma metastasis in the sentinel lymph node(s) is not only an important prognostic indicator but also dictates whether the patient will receive further surgery and adjuvant chemotherapy. Therefore, the goal of the pathologist in examining the sentinel lymph node is to maximize identification of nodal metastases of malignant melanoma. This is accomplished by following a standard protocol which fully utilizes all tissue submitted in concert with commonly available immunohistochemical techniques.

The incidence of melanoma is rising globally despite increased awareness. Familiarity with the clinical signs and certain risk factors for melanoma can result in early recognition, and potentially influence outcome. Unfortunately, there are several other cutaneous tumors, both malignant and benign, that resemble melanoma, and may confuse and possibly delay the diagnosis. This paper discusses the clinical characteristics of melanoma and its most common pigmented simulators.

Objective: The purpose of this study is to emphasize the instrumental role of preoperative lymphoscintigraphy in the surgical treatment of patients with malignant melanoma.

Summary background data: The efficacy of lymphoscintigraphy is reflected in its ability to reveal cutaneous lymphatic drainage to regional nodal basins that are at risk for melanoma metastases but not necessarily discernable to be at risk through standard historical anatomical guidelines or clinical experience. This preoperative lymphatic mapping technique has contributed greatly to the accuracy and efficiency of staging procedures including sentinel node biopsy and elective lymph node dissection.

Patients and methods: After informed consent, a selected series of four patients with primary melanomas located in watershed areas of the body (left neck, right mid-abdomen, right scapula, left back) and two patients with extremity melanomas (right distal forearm and left ankle) underwent pre-operative lymphoscintigraphy to identify all basins for metastases.

Results: In all of the cases, lymphatic drainage occurred in an unusual and unexpected basin that could not have been predicted clinically and in three of the cases the resected basins contained positive sentinel nodes. If not for the preoperative lymphoscintigraphy, these nodal basins would not have been resected and metastatic disease would have been left behind. In addition, the staging of the melanoma patient would have been inaccurate.

Conclusion: If the sentinel node biopsy of elective lymph node dissection (ELND) were based on clinical predictions only, nodes equally at risk for metastatic disease would not have been resected and in some cases, nodal basins not at risk for metastases would have been resected unnecessarily. Without lymphoscintigraphy, the validity and efficacy of the ELND or the sentinel node biopsy for nodal staging is greatly compromised. These six case studies illustrate the difficulty of predicating lymphatic drainage from primary sites located on the head and neck, truck and even the extremities and demonstrate the indispensability of preoperative lymphoscintigraphy in the management of malignant melanoma.