Sentinel Lymph Node Biopsy in a Young Child With Thick Cutaneous Melanoma

The surgical management of cutaneous melanoma remains controversial in part because there is no consensus regarding the margins of excision for the primary tumor or the therapeutic benefit of removing clinically normal appearing regional lymph nodes (elective lymph node dissection).[1] Intraoperative lymphatic mapping with sentinel lymph node dissection has revolutionized the management of regional lymph nodes by allowing the surgeon to perform a minimally invasive procedure instead of elective lymph node dissection, and by allowing the pathologist to focus on one or two lymph nodes rather than all the nodes in a complete lymph node dissection specimen.[2] Intraoperative mapping is performed by preoperative cutaneous lymphoscintigraphy; intraoperative identification of the sentinel lymph node relies on residual radioactivity from lymphoscintigraphy or on coinjection of a radiopharmaceutical with a vital blue dye.[3] Long-term experience suggests that lymphatic mapping by a multidisciplinary team composed of a nuclear medicine physician, surgeon, and pathologist can be performed after a short learning period.[4] Sentinel Lymph Node Dissection
The tumor status of the sentinel lymph node is prognostically important; patients with a tumor-positive sentinel node have a significantly worse survival than do those with tumor- negative dissections. The tumor status of the sentinel node supersedes all other prognostic features of the primary.[5] Recurrences are rare in lymphatic basins that contain tumornegative sentinel nodes, suggesting the high accuracy of the technique. However, because the therapeutic benefit of identifying metastatic disease at an early stage has not been proven, surgeons struggle to determine which patients with positive sentinel nodes should undergo complete lymph node dissection. Most patients with positive sentinel nodes will have no other involved nodes. Should these patients still undergo completion dissection? Complicating the question is the equivocal role of adjuvant therapy with high-dose interferon, its associated toxicity, and the failure of other experimental regimens to show a significant impact on survival.[6,7] Contemporary Melanoma Management Strategies
In this issue of ONCOLOGY, Bisseck and associates from Wake Forest University describe the management of a 4-year-old boy with a Clark level IV, 5-mm ulcerated melanoma on the right cheek. After a staging work-up, the patient underwent wide excision of the melanoma with sentinel lymphadenectomy of a cervical lymph node and delayed completion lymph node dissection. A single positive sentinel node was obtained from the right neck dissection. This case illustrates contemporary management strategies for cutaneous melanoma-a disease that rarely occurs in childhood. Most modern medical literature suggests that the natural history of melanoma in children is similar to that of adults, but too few pediatric cases are reported in the literature to gain meaningful insight into this disease in children. We, as clinicians, are forced to extrapolate therapeutic options for children from the adult experience.[8,9] Children are typically diagnosed with thick primaries, as in this case, because the differential diagnosis of a pigmented skin in children rarely includes melanoma.[10,11] Unfortunately, patients with thick (> 4 mm) primary melanoma may already have subclinical distant metastases at the time of diagnosis. Computed tomography scans or whole-body positronemission tomography scans can reveal subcentimeter tumor foci but are less likely to identify metastases smaller than a few millimeters in size. Sentinel lymphadenectomy is the only useful guide for surgeons to identify microscopic metastases, and thus, has become an important staging tool. It is possible that pediatric patients with thick primary melanomas can benefit from sentinel lymphadenectomy, as most adult patients with a single positive sentinel node will achieve long-term survival.[12,13] Yet many patients will die from recurrent melanoma. The long-term survival of the child in this case is unknown. Traditional techniques of following patients with serial blood work and radiographic studies have never been shown to prospectively predict recurrence. Conclusions
Perhaps through the development of newer molecular-based approaches for screening serum and tumor specimens, the outcome of patients with a single-tumor-positive sentinel node will be better understood. Meanwhile, improved public awareness and education should be used to diagnose these lesions at an early stage and, potentially, to decrease the incidence of skin cancers in all age groups.[14]