Differences in tumor microvessel density between squamous cell carcinomas and basal cell carcinomas may relate to their different biologic behavior.

Tumor microvessel density (TMVD) has been recognized as an important indicator for the metastatic risk in certain tumors. The purpose of this study was to analyse whether there is an association of TMVD in epithelial neoplasms of the skin with their clinical behavior. Paraffin sections of keratoacanthomas (KA, n = 10), squamous cell carcinomas (SCC, n = 9), nodular (nod-BCC, n = 13), and sclerosing (scl-BCC, n = 12) basal cell carcinomas were immunohistochemically stained for factor-VIII-related antigen and TMVD was determined. In all SCC, KA and nod-BCC, TMVD significantly exceeded perilesional skin microvessel density (PSMVD) (SCC:TMVD/PSMVD = 20.54:11.25, p < 0.0001; KA:TMVD/PSMVD = 20.90:12.17, p < 0.0001; nod-BCC:TMVD/PSMVD = 16.77:13.34, p = 0.03). In contrast, no significant difference between TMVD and PSMVD was found in scl-BCC (15.44:12.86, p = 0.22). TMVD was significantly higher in SCC and KA compared to nod-BCC (p = 0.036 and 0.006, respectively). Our data demonstrate that SCC and KA are highly vascularized tumors. The fact that TMVD does not differ significantly between SCC and KA (p = 0.80) suggests that MVD is not an indicator for the metastatic risk or aggressive growth behavior of epithelial skin tumors. The finding that MVD in both nod- and scl-BCC is significantly lower than in SCC and KA, might at least in part explain the slow growth of BCC.