Dermoscopic evaluation of vascular structures of various skin tumors in Japanese patients.

Dermoscopic analysis of skin tumor has been mainly focused on pigmented structures. Recently, several different morphological types of vessels were found to be well associated with pigmented or non-pigmented skin tumors in white subjects. Therefore, the recognition of such vascular structures has been applied for diagnostic purposes. As little statistical information on the various pigmented skin tumor vessels of Japanese patients has been reported, we therefore tried to evaluate the association between various vascular structures and 741 tumor lesions of Japanese patients. Vascular structures were dermoscopically recognized in 41 of 102 cases of melanoma, 104 of 119 basal cell carcinoma (BCC), 86 of 257 seborrheic keratosis (SK), 35 of 210 dermal and compound nevus (DN/CN), six of 12 squamous cell carcinoma (SCC) and 16 of 41 Bowen disease (BD). The structures of arborizing and glomerular vessels statistically revealed diagnostic specificity for BCC and BD, respectively, and hairpin vessels were helpful for differentiating SK from other pigmented tumors, as already reported in white patients. The most common vascular pattern observed in melanoma was the linear-irregular structure, but this pattern in Japanese patients had less diagnostic value than in white patients, because its sensitivity was not significantly higher than in SCC. The most remarkable differences between our study and previous reports with white patients were low frequency and sensitivity of dotted, comma and polymorphous vessels in lesions of melanoma, BCC and DN/CN; these vessels had less diagnostic value for Japanese patients. Finally, the frequency of vascular structures observed in melanoma rose along with the increase of the Breslow's tumor thickness, and 88% of melanomas with vascular vessels revealed tumor thicknesses of more than 2 mm.