Possible histopathologic correlates of dermoscopic features in pigmented melanocytic lesions identified by means of optical coherence tomography

Optical coherence tomography (OCT) is a novel non-invasive imaging technique for in vivo histologic characterization of tissues. Besides pure morphology, additional functional parameters of the tissue investigated can be evaluated at the same time, such as the refractive index and the scattering coefficient. The purpose of our study is to correlate in vivo the dermoscopic structures that first appear in the melanocytic pigmented lesion (pigment network and brown globules) using this new method, with the histopathologic correlates, in order to improve their characterization and achieve easier recognition and inter-observer reproducibility. We concentrated in particular on the pigment network and the brown globules, as these are dermoscopic parameters of great diagnostic importance in melanocytic lesions. Moreover, as these parameters are the histopathologic equivalents of structures located at the level of the dermo-epidermal junction, they enable a correct evaluation to be made using OCT, that at present has only a few millimetres penetration power. The results of our trial, performed using the histopathological preparation as an evaluation gold standard, show that in selected cases OCT allows an in vivo correlation to be made between surface dermoscopic parameters and histopathologic correlates, in particular the pigment network and brown globules. The resolution is not high enough to reveal the morphology of the single cells, but it is possible to evaluate the architecture of a lesion.