[451] Microscopic Imaging of Lymphangiogenesis in Cutaneous Malignant Melanoma: Still a Questionable Predictor of Sentinel Lymph Node Metastasis

G Falconieri, G DeMaglio, D Camilot, S Pizzolitto. General Hospital, Udine, Italy

Background: Several parameters have been devised to predict sentinel lymph node (SLN) involvement in infiltrating cutaneous malignant melanoma, including tumor thickness, microscopic depth (or Clark level) of invasion, vascular involvement, ulceration, and decreased peri- and/or intratumoral lymphoid infiltration. However, the role of lymphangiogenesis in melanoma is not clear, and specific studies addressing lymphatic vessel density (LVD) and SLN status are underreported.
Design: All cases of invasive melanoma microscopically featuring more than 0.75 mm thickness with available SLN biopsy were retrieved. Paraffin sections from primary tumors were stained with monoclonal antibody D240 (or podoplanin) obtained from a commercial source. Histologic sections were adequate if they had at least 5 microscopic tumor fields for scanning at 20x magnification when using a 25x eyepiece. LVD per square millimeter was assessed by counting lymphatics on at least 5 consecutive tumor fields. Microscopic assessment of extratumoral lymphatic involvement was also carried out.
Results: A total of 136 melanomas fulfilling the design criteria were included in the study. Metastatic SLNs were seen in 29/136 cases (21.3%). In positive SLN cases, LVD in primary melanoma ranged from 0.05 to 1.84 per square millimeter (average 0.34); in negative SLN cases, LVD ranged from 0.05 to 5.1 per square millimeter (average 1.29), P=0.34. Microscopic involvement of peritumoral dermal/hypodermal lymphatics was documented in 7/29 melanomas associated with a positive SLN and in 4/107 cases of negative SLN biopsy (P=0.005).
Conclusions: A low LVD in invasive melanoma is more frequently associated with a positive SLN, although the difference was found to be not statistically significant. Involvement of extratumoral lymphatics proved to be a better predictor of SLN metastases.
Category: Dermatopathology

Wednesday, March 11, 2009 9:30 AM

Poster Session V # 49, Wednesday Morning