Malignant melanoma in the pediatric population

Controversial pigmented lesions in children are a problem for pathologist, clinicians and families that are confronted with this dilemma. Some skin lesions in this population defy diagnosis with pathologists split between a benign diagnosis and a cancer diagnosis. Three cases of controversial pigmented lesions in the pediatric population are presented. Three patients underwent radical resection of the controversial pigmented lesion, intra-operative lymphatic mapping and sentinel lymph node (SLN) biopsy. Due to the low morbidity of the SLN procedure a case is made to perform lymphatic mapping in this clinical scenario. If the SLNs are negative, not much is lost except for the scar and this becomes another line of evidence that perhaps the original lesion was benign. If the SLN shows metastatic cells, then the original skin lesion must be malignant and the patient is offered stage III recommendations that would include complete node dissections and adjuvant Interferon therapy. This strategy provides for adequate treatment of the worse-case scenario, that the skin lesion is malignant. The cost to the patient is a low morbidity procedure, the SLN biopsy.

Evidence for a better nodal staging system for melanoma: the clinical relevance of metastatic disease confined to the sentinel lymph nodes

BACKGROUND

The hypothesis tested in this study was whether patients with stage III metastatic melanoma confined to their sentinel lymph nodes (SLNs) had a more favorable prognosis than patients who had SLN and non-SLN (NSLN) metastases.

METHODS

Patients were identified who were clinically negative in their regional basins but with lymphatic mapping were found to have positive SLNs (331 patients). All patients subsequently underwent a complete lymph node dissection of the lymphatic basin involved, and the total number of metastatic SLNs and NSLNs were documented.

RESULTS

As the regional metastatic disease involves NSLNs, disease-free survival (DFS) and overall survival (OS) decreases. For patients with a total of 2 nodes positive, those with disease confined to the SLNs had a significant better prognosis (DFS and OS: P < .00001) than those in whom 1 SLN and 1 non-SLN was involved. This difference was apparent for those patients with N2 and N3 disease (2 or more nodes positive in their regional basin). A multivariate regression analysis that included Breslow thickness, ulceration, number of positive nodes, and NSLN positivity showed that NSLN positivity (P = .0019) was the most powerful predictor of DFS and OS.

CONCLUSIONS

When metastatic melanoma overwhelms the SLN and involves NSLNs, the biologic behavior changes to portend a worse survival, regardless of the total node count positive. These data make the argument that the current N staging system should be changed to incorporate SLN vs NSLN involvement.