Dermoscopy has recently proven to be a valuable method for improving the clinical diagnosis of melanoma. The classic approach for diagnosis in dermoscopy is the so-called pattern analysis set forth by Pehamberger and colleagues in 1987. This widely used diagnostic method is based on a critical, simultaneous assessment of individual dermoscopic criteria improving the rate of correct diagnosis of pigmented skin lesions by 10% to 30%. Nevertheless, because of problems inherent to the reliability and reproducibility of the diagnostic criteria used in pattern analysis, two additional diagnostic methods based on diagnostic algorithms have been introduced in the last few years with the aim to increase sensitivity in detecting cutaneous melanoma. For both methods, ABCD rule of dermatoscopy and 7-point checklist, first a given pigmented lesion must be classified as melanocytic or non-melanocytic. This melanocytic algorithm is shown in detail in the table. Only when the diagnosis of a non-melanocytic lesion is ruled out and a melanocytic lesion is diagnosed, can these methods be applied.

  1. The ABCD rule of dermatoscopy, based on a semiquantitative analysis of the asymmetry, border, color, and different dermatoscopic structures of a given melanocytic lesion [Stolz et al. 1994, Nachbar et al. 1994]. The ABCD rule is thought to be helpful also for clinicians not fully experienced in dermoscopic observation, being simpler than pattern analysis [Binder et al. 1995, Binder et al. 1997].

  2. A new algorithm, called 7-point checklist, providing a quantitative scoring system and a simplification of the classic pattern analysis due to the lower number of features to identify. This method was developed for the dermoscopic diagnosis of melanoma based on a blind evaluation of 342 melanocytic skin lesions (117 melanomas and 225 clinically atypical nevi) [Argenziano at al. 1998].

Melanocytic Algorithm (Modified according to Stolz et al. 1994)
  Dermoscopic criteria Diagnostic significance
I STEP Pigment network (also present in solar lentigo and seborrheic keratosis on facial skin as well as in dermatofibroma)

Brown to black dots/globules


Homogeneous blue pigmentation
(dermoscopic hallmark of blue nevus)

Parallel pattern
(on palms and soles)
Melanocytic lesion
II STEP Milia-like cysts

Comedo-like openings
(irregular crypts)
Seborrheic keratosis
III STEP Leaf-like areas

Arborizing vessels

Irregular gray-blue
globules and blotches
Basal cell carcinoma
IV STEP Red lacunas

Red-bluish to red-black homogeneous areas
Vascular lesion (including hemorrhages)
V STEP Central white patch (surrounded by delicate pigment network)
VI STEP None of the above criteria
Melanocytic lesion



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