Lymphatic invasion detected by D2-40/S-100 dual immunohistochemistry does not predict sentinel lymph node status in melanoma

Background: Sentinel lymph node biopsy provides important prognostic information with controversial therapeutic advantages. D2-40 is a novel immunohistochemical stain specific for lymphatic endothelium often utilized to study tumor lymphangiogenesis and lymphatic invasion. Objective: To increase the detection of lymphatic invasion in primary cutaneous melanomas with D2-40/S-100 dual immunohistochemistry, and then apply the technique to melanomas with known sentinel lymph node status. The primary aim was to assess whether the presence or absence of lymphatic invasion could predict sentinel lymph node status. The secondary aims were to assess whether lymphatic invasion and/or sentinel lymph node involvement were associated with clinicopathologic parameters commonly studied in melanomas. Methods: Twenty-seven biopsy specimens of primary cutaneous melanoma from 27 patients with known sentinel lymph node status were retrospectively reviewed and labeled with D2-40/S-100 dual immunohistochemistry. The following clinicopathologic variables were evaluated: age, gender, histologic type, Breslow thickness, Clark level, ulceration, mitoses, lymphovascular invasion by routine staining and D2-40/S-100 dual immunohistochemistry, and overall survival. Statistical analyses were performed to assess for associations. Results: D2-40/S-100 dual immunohistochemistry showed unequivocal lymphatic invasion in 10 of 27 melanomas compared with 1 of 27 with routine histology. Eight of 10 melanomas with lymphatic invasion were sentinel lymph node negative. There was no statistical association between the presence or absence of lymphatic invasion and sentinel lymph node status. Limitations: The major limitation was the small sample size. Conclusion: D2-40/S-100 dual immunohistochemistry increases the sensitivity of detection of lymphatic invasion in melanoma but does not predict sentinel lymph node involvement.