Correlation between digital epiluminescence microscopy parameters and histopathological changes in lentigo maligna and solar lentigo: A dermoscopic index for the diagnosis of lentigo maligna.

BACKGROUND: The clinical and dermoscopic differentiation between lentigo maligna (LM) and solar lentigo (SL)/initial seborrheic keratosis (SK) may be difficult.

OBJECTIVE: Our aim was to identify digital epiluminescence microscopy (DELM)-specific criteria that can be helpful in distinguishing LM from SL/SK and to propose a new model of LM dermoscopic progression based on a study of DELM-histopathological correlation.

METHODS: A total of 167 consecutive doubtful pigmented lesions of the head (105 LM and 62 SL/SK) were studied. DELM assessment was based on the presence or absence of 15 DELM parameters that were subsequently examined histologically. Statistical analysis was performed to determine which DELM parameters were most strongly associated with LM.

RESULTS: The finding of at least 1 of 4 parameters (ie, brown globules, a "necklace" pigment network, an atypical pigment network, and dark-brown/blue-gray ribbonlike structures) showed to be an extremely sensitive (99%) and specific (83.9%) DELM criterion to discriminate between LM and SL/SK.

LIMITATIONS: Our findings were obtained by examining medium-high magnification DELM images.

CONCLUSIONS: The finding of 1 or more among the 4 above-mentioned DELM parameters allows for the correct identification of 99.0% of the LM lesions, and - when the score is 0 - the correct classification as non-LM, of 83.9% of the SL/SK lesions.