Dermoscopy (dermatoscopy, epiluminescence
microscopy, incident light microscopy, surface microscopy)
is widely used nowadays for the diagnosis of pigmented skin
The method is getting more and more
popular, not only among dermatologists, but also among oncologists,
and even general physicians. However, there is still a need
for better standardization of the dermoscopic
terminology, which has not been reviewed since the last (and
only) Consensus Meeting on Dermoscopy
was held in Hamburg more than ten years ago, in November, 1989.
With a new Consensus Meeting,
we will attempt to refine the dermoscopic terminology and to
simplify the diagnostic categories
of pigmented skin lesions. Because dermoscopic images today
can be easily transmitted
via telecommunication devices, we plan to organize a virtual
Consensus Meeting via the Internet,
known as the Consensus Net Meeting on Dermoscopy (CNMD).
To prove the validity of a two-step procedure
for the dermoscopic classification of pigmented skin lesions.
Consensus on terminology of dermoscopic criteria
by refinement of established criteria and definition
of new criteria
Diagnostic categories, as far as diagnosable
Consensus on management decisions based on
Consensus on follow-up strategies, including
Consensus on validity of teledermoscopy and
elaboration of standard requirements for teledermoscopy
The Preliminary scientific design, including
the Web design, was presented during an informal meeting in
San Francisco at the AAD meeting on March 10, 2000. The Materials
and Methods section has since been refined based on the comments
and suggestions of the participants. The actual CNMD will start
on July 1 and last until October 31, 2000.
First World Congress of Dermoscopy Rome, February 23-25, 2001
The results of the CNMD will be
discussed with Consensus Board Members at the World Congress
of Dermoscopy in Rome.
Materials and Methods
Pigmented skin lesions included in this
study are taken from the histopathology files of the Department
of Dermatology, University Federico II of Naples (Italy);
the Department of Dermatology, University of LAquila
(Italy); the Sydney Melanoma Unit, Royal Prince Alfred Hospital,
Camperdown (Australia); and the Skin and Cancer Associates,
Plantation, Florida (USA). Each case includes complete information
regarding relevant clinical* and histopathologic data as
well as clinical and dermoscopic images and histopathologic
age, sex, skin phototype, total number
of nevi (0-10, 10-50, >50), personal and/or familial
history of melanoma;
location, diameter, and duration of the
lesion, as well as the history concerning any morphologic
changes within the last year before the excision of the
b) Standards used for Digital Documentation
of Dermoscopic Images (DDDI-standard)
Clinical and dermoscopic images of each
case will be obtained using a Heine Dermaphot, with 10-fold
magnification of the lesion. The color slides will be converted
to digital format using a Kodak Photo CD system.
Using Adobe Photoshop software all Photo
CD images (RGB, 768 x 512 pixel, 72 DPI)
will be converted to jpeg format with high compression rate.
Each image will then be optimized for color, brightness,
and contrast by using the Adobe Photoshop standards (Auto
levels and Unsharp mask).
c) Criteria for Cases Selection
Before inclusion in the study all digital
images will be evaluated by a professional photographer
for focus, brightness and contrast. Only images with excellent
quality will be considered for inclusion.
Only those lesions having a clinical diameter
of less than 14 x 10 mm will be included. This is a basic
prerequisite in order to evaluate the entire surface of
Each case will then be included in one of
two groups of pigmented skin lesions:
1) Stereotypical examples (low level of diagnostic difficulty);
2) Dermoscopically equivocal examples (high level of diagnostic
All cases will be evaluated by 3 participants
for their level of diagnostic difficulty.
Each case will be assigned to group 1 or 2 by the agreement
of at least 2 out of 3 evaluators.
All cases will be reviewed by a panel of
histopathologists and only histopathologically
unequivocal lesions will be included in the study.
128 pigmented skin lesions will be randomly
subdivided in a training set of 20 cases and a test
set of 108 cases.
On the Internet a tutorial will be given
concerning the unifying concept of dermoscopy
(with complete definitions of criteria and example images).
By entering a password each participant will
be able to evaluate 20 cases from the training set.
For each case, the participants will complete an electronic
Immediately following submission of the completed electronic
data sheet, the participants
will receive the set of dermoscopic criteria of that case
as judged by the instructors
and the histopathologic diagnosis provided by the histopathology
This "real-time feedback" should assist the participant
in mastering the dermoscopic criteria.
Each participant will then be able to evaluate on-line 108
cases of the test set.
A total of 4 months (July 1 to October 31, 2000) will be
given for evaluating the cases.
At the end of the evaluation period, participants
will re-examine 20 randomly selected cases
from the test set of 108 cases, to test for intra-observer
The histopathologic diagnoses for all cases
will be posted on the web site after October 31, 2000,
following evaluation of all cases of the test set and evaluation
of the additional 20 cases
for determining intra-observer agreement.
The minimum required resolution for viewing
cases is 800 x 600 pixels and 24-bit color graphic capability.
At the beginning of the study all participants
will be asked to complete a questionnaire concerning their
personal experience in dermoscopy and their preferred diagnostic
methods, as well as their computer system specifications.
This information will be useful in understanding whether
the variability of the dermoscopic methods used in clinical
practice, the different learning curves and training experiences,
and the various computer systems used are affecting the
intra- and inter-observer agreement
on dermoscopic criteria and dermoscopic diagnoses.
Electronic Data Sheet for evaluation of cases
This will include:
Clinical information concerning lesion and
patient (see Materials section)
Melanocytic algorithm for differentiating
melanocytic and non-melanocytic pigmented skin lesions
Criteria for diagnosing melanocytic lesions
by pattern analysis
Criteria for the ABCD rule with automatic
calculation of the score
Criteria for the 7-point checklist with automatic
calculation of the score
Criteria for the Menzies' method with automatic
calculation of the score
Diagnostic categories for the final diagnosis
together with management recommendations and final remarks
Rates of inter- and intra-observer
agreement will be analyzed by calculating the percentage of
agreement and determining the k index for agreement compared
with that expected by chance alone for each descriptor considered
[Fleiss LJ, 1981]. Subgroups of descriptors will be compared
for distribution of the associated k values by means of two-tailed
Wilcoxon rank-sum test. A k value of 1.0 indicates full agreement
beyond chance. Values greater than 0.75 are generally considered
excellent, values between 0.40 and 0.75 fair to good, and values
less then 0.40 poor [Fleiss LJ, 1981]. A p value <= 0.05
(two-sided) will be considered statistically significant.
Donner's method will be used
to calculate the sample size for testing two coefficients of
inter-observer agreement [Donner A, 1998; Walter et al, 1998].
The sample size requirement for comparing two coefficients of
inter-observer agreement will be calculated for dichotomous
and continuous outcome variables.
In order to measure intra-class
agreement between parameters, for each group we calculated two
different numbers of cases necessary to detect both a moderate
and a substantial strength of agreement. Choosing the level
of significance as alpha=0.05 and power (1-beta=0.80) for testing
H0: K1=K2 versus H1: K1 <> K2, the required sample size
for group testing would be 36 cases for moderate (k index of
agreement = 0.41-0.60) and 97 cases for substantial strength
of agreement (k= 0.61-0.80).
Additional statistical analysis
will be conducted to test the validity of procedures to detect
For this reason, cases will be divided in two groups (melanoma
and non-melanoma), based on results of the histopathologic assessment.
Using a univariate analysis, the relationship of each criterion
with the diagnosis of melanoma will be evaluated by chi-square
analysis. Logistic regression analysis will be used to test
the diagnostic impact of the whole set of dermoscopic criteria
in a multivariate approach, and the probability of each case
belonging to the group of melanomas will be calculated. Sensitivity,
specificity, efficacy and diagnostic accuracy will be assessed
for clinical diagnosis, dermoscopic diagnosis, and the diagnosis
provided by the logistic regression approach.
Donner A. Sample size requirement
for the comparison of two or more coefficients of inter-observer
Statist Med 1998;17:1157-1168.
Walter SD, Eliasziw M, Donner A.
Sample size and optimal designs for reliability studies.
Statist Med 1998;17:101-110.
Fleiss LJ. Statistical methods for
rate and proportions. 2nd ed. New York, John Wiley &
Sons, 1981: 212-236.