in the pre - dermoscopic era , melanoma diagnosis was based only on clinical morphology and on the simple  abcd  rule ( asymmetry , border irregularity , color , diameter ) . dermoscopy or dermatoscopy   is a non - invasive technique that consists of viewing pigmented skin lesions through a hand - held lens , a dermatoscope or a video imaging system . this procedure allows physicians to observe structures and colors not otherwise visible to the unaided eye , increasing melanoma diagnostic accuracy by up to 35% . the conventional dermoscopic diagnosis is based on the assessment of specific criteria and on the application of different diagnostic algorithms . in recent years , polarized light dermatoscopes gradually overtook non - polarized light devices , which were introduced in the 1990s and are still used today . since its introduction in the mid-1980s , and thanks to more than 1500 publications , dermoscopy has developed and dramatically become a well - established , routine technique in many european countries and australia . nevertheless , in other countries , like the united states , dermoscopy still struggles to be accepted in daily clinical practice . herein , we reviewed the most recent important advances in dermoscopy of melanocytic lesions published in the last three years in english literature . other applications of dermoscopy for non - melanoma skin cancers and other skin conditions are beyond the scope of this review . the time for dermoscopic examination of nevi is basically double that required for a naked - eye examination ( 142 vs 70 seconds ) , but still under 3 minutes - a reasonable time for a correct skin cancer screening . dermoscopy reduces the number of unnecessary excisions , thanks to the improvement of diagnostic accuracy . showed that , in specialized clinical settings , the introduction of dermoscopy leads to a reduction of excised nevi and to an increased number of diagnosed and excised melanomas . with dermoscopy , non - specialist clinicians are able to improve the malignant / benign ratio of excised lesions   and even non - clinicians can identify suspicious lesions   simply by applying a simple method like the ac rule ( asymmetry and color variation ) . and others   revised the 7-point checklist in a 10-year prospective study and found this method highly specific but less sensitive . in fact , 38% of melanomas scored less than 3 points ( in situ melanomas frequently only scored 1 point ) using the checklist and were identified only thanks to additional information such as anamnestic data , the ugly - duckling sign and signature nevi   or changes at digital follow - up . regression patterns , atypical vascular patterns and radial streaming were associated with the highest relative risk for melanoma . argenziano et al . revised the 7-point checklist , reducing the original 3-point threshold to 1-point in order to identify more melanomas . this gave higher mean rates of excision with an increased sensitivity but a lower specificity compared with the original 7-point checklist and pattern analysis . the authors recommend using the revised algorithm in a daily clinical setting , integrating dermoscopy with clinical information and follow - up . recently described a new melanoma predictor , the dermoscopic island , which differs from the eccentric pigmentation described by arevalo et al . . the dermoscopic island is defined as a circumscribed area showing a different dermoscopic pattern from the rest of the lesion ( reticular , globular , homogeneous or starburst pattern ) located at the periphery or in a paracentral position . it is more frequently observed in in situ and thin melanomas than in nevi , and represents the morphological aspect of initial malignant transformation . eccentric pigmentation represents an area of asymmetrical pigment distribution and lesions showing this feature , but lacking other specific criteria for melanoma , do not require closer follow - up than other nevi . the use of polarized light in dermoscopy allows the recognition of some structures not visible with non - polarized light . some authors proposed changing this term to crystalline structures , to include short white lines , white strands , white clods or white areas and rosettes . short white lines arranged in an orthogonal fashion may be observed not just in melanomas and spitz nevi but also in basal cell carcinomas , squamous cell carcinomas and dermatofibromas . described a new predictor of nodular melanoma , the blue - black color due to the combination of pigment localized in the mid - deep dermis ( blue ) and , in atypical melanocytes , in the epidermis ( black ) . the authors found a higher sensitivity for blue - black color with respect to standard criteria in the diagnosis of nodular melanoma ( 78.2% vs 43.6% respectively ) . the blue - black color is a useful new feature allowing the diagnosis of some melanomas lacking standard criteria . .   looked at hypomelanotic and amelanotic melanoma and found blue - white veil , scar - like depigmentation , multiple blue - gray dots , irregular - shaped depigmentation , brown dots / globules irregular in size or distribution , five to six colors and predominant central vessels to be the most positive predictors of melanoma . in contrast , three or more milia - like cysts , comma vessels with regular distribution or the predominant vessel type , symmetrical pigment distribution , irregular or multiple blue - gray globules are the most significant negative predictive factors in melanoma diagnosis . accuracy of dermoscopic criteria is lower for hypomelanotic - amelanotic melanoma than with pigmented melanoma , but still superior to naked - eye examination . sequential digital dermoscopy imaging ( sddi ) is crucial in identifying melanomas lacking the specific criteria of malignancy . unlike long - term follow - up ( 6 - 12 months ) , any morphologic change detected on short - term 3-month follow - up serves as a reliable prompt for the physician to excise the lesion . in contrast , lesions not showing dermoscopic changes on follow - up imaging can be left to avoid unnecessary excision . three - month follow - up remains the correct interval ( rather than 6 weeks ) to diagnose featureless melanoma . three months is also the recommended follow - up period for high - risk patients , such as those with familial atypical mole and multiple melanoma ( fammm ) syndrome , but 6 - 12 months is better for those with atypical mole syndrome . short - term follow - up is also the best strategy to optimize patient compliance . patients addressed to a short - term follow - up are more likely to return compared with long - term follow - up patients , probably because of the major concern about a lesion to be checked after only 3 months . described a series of 103 melanomas diagnosed and excised after long - term follow - up with minimal dermoscopic changes , with respect to the baseline visit ( mean follow - up time : 20 months ) and still in situ or thin at the time of histopathological diagnosis . melanomas showing a reticular pattern on baseline image are more likely to remain in situ , whereas those with a non - reticular pattern usually show major changes at follow - up control . this supports the theory that melanoma represent a family of tumors : rapidly growing melanomas with a high capacity to metastasize , on the one hand , and slowly growing lesions often detectable only after repeated follow - up visits , on the other . correct use of sddi allows us to increase diagnostic accuracy , and reduce the number of undetected melanomas and also unnecessary excisions . dermoscopy also allows us to study the physiology of nevi ( clusters of pigmented skin cells ) . some people have a high propensity to develop nevi , others lower , and this propensity is genetically established and , in part , due to environmental factors . the number of nevi is small in childhood , increases during adolescence and mid - life , and finally decreases during late adulthood [ 40 - 42 ] . the dermoscopic pattern of nevi seems to be age- and site - related , with a prevalence of globular nevi on the trunk in childhood ( which tend to persist ) , and reticular nevi appearing on the upper back and extremities in adulthood ( which tend to fade over time ) . these data led zalaudek et al . to prepare two different pathways for nevogenesis : the constitutional pathway gives rise to congenital globular nevi in childhood ; and the acquired pathway is responsible for arising nevi with a prevalent reticular pattern in adolescence and adulthood . proposed a new dermoscopic classification of melanocytic nevi into seven groups based on specific dermoscopic features that identify those lesions as specific entities ( table 1 ) . the original clinical description of a pink - red papulonodular lesions on the face and extremities of children or black ( reed nevus ) papules or plaques on the extremities is no longer optimal for diagnosis . dermoscopy completely changed this view by identifying three main dermoscopic patterns : globular , starburst and multicomponent ( atypical , melanoma - like ) . similar to acquired nevi , spitz / reed nevi follow an evolution / involution process . in the evolution , or growing phase , spitz / reed nevi show the classical starburst pattern , which is subsequently replaced after a variable number of months by a homogenous pattern observed during the stability phase . after some years , lesions gradually lose pigment and finally disappear , indicating that involution is common . however , the recommendation is to excise nevi with spitzoid features in patients older than 12 years . the braf oncogene is highly expressed in acquired nevi , whereas other types of melanocytic nevi  such as congenital dermal nevi , spitz , and blue nevi  are usually characterized by mutations in other genes . braf mutations induce melanocyte proliferation , forming neoplastic clones . without any other genetic alteration , such as that induced by intermittent uv exposure , braf mutations are probably acquired early in nevogenesis and their level of expression is correlated with the phase of growth . based on this theory , it seems that young benign reticular nevi express high levels of braf mutations , slowly decreasing with nevus growth , followed by a final low rate in senescence . dermoscopy has dramatically improved the diagnostic accuracy of melanocytic skin lesions and , more recently , is helping us understand nevogenesis mechanisms and nevus physiology . new advances in terms of optimal application and follow - up and newly described criteria have gradually allowed us to correctly diagnose melanoma even in very early stages , where rates of curability and survival are high . this success may be an argument for a more widespread application of dermoscopy to screen the wider asymptomatic community on a routine basis .
over the last 30 years dermatological approaches to diagnosis and management of melanocytic lesions have been revolutionized by the introduction of dermoscopy . 
 continuous improvements are being made in applying the technique , mostly in melanoma diagnosis , follow - up of melanocytic lesions and nevogenesis . 
 identification of new dermoscopic criteria , such as the dermoscopic island and the blue - black color for thin and nodular melanoma , respectively , further add two new weapons in the dermoscopical armamentarium for diagnosis of otherwise featureless melanoma . 
 recent advances show that short - term , 3-month , follow - up is the optimum time interval to identify minimal changes in initially featureless melanomas . nevertheless , long - term follow - up is still useful for the recognition of changes in melanomas with a very low - rate of growth . 
 dermoscopy greatly improves diagnosis and early excision of melanomas and reduces the number of unnecessary excisions .