Dermatoscopy

Dermatoscopy

An Algorithmic Method for Accurate Diagnosis
Harald Kittler, MD, Philipp Tschandl, MD
Diagnose pigmented lesions of the skin by dermatoscopy
About the authors | Introduction to the method | Algorithm for a specific diagnosis
Clinical Reference / Dermatoscopy / Introduction to the method

How to identify pigmented skin lesions with specificity

  1. Elements basic
  2. Patterns basic
  3. Colors
  4. Clues to specific diagnoses
  5. Algorithm for a specific diagnosis

1. Elements basic

2. Patterns basic
Those formed of a single element such as lines, pseudopods, circles, clods, or dots.

Summary of patterns basic

Lines
Reticular
Branched
Parallel
Radial
Curved
Pseudopods
Circles
Clods
Dots
Structureless (no pattern)

Variations of patterns basic created by lines

  • Lines reticular can be thin or thick
  • Lines branched can be thin or thick
  • Lines parallel on glabrous skin can follow furrows or ridges, or they can cross furrows and ridges
  • Lines radial can be thin or thick. Lines radial may be present at the periphery of the lesion (peripheral) or in the center of the lesion (central). Peripheral lines radial may be circumferential or segmental. Central lines radial usually are present in multiple foci and converge to a central dot or clod
  • Lines curved can be thin or thick, short or long

Variations of patterns basic created by circles, clods, or dots

  • Circles can be sparse or dense, discrete or confluent
  • Clods can be sparse or dense, small or large, equal in size and shape, or unequal in size and shape
  • Dots can be sparse or dense

3. Colors

4. Clues to a specific diagnosis

Lesions NOT melanocytic

Intracorneal hemorrhage

Clues

  • Red clods (fresh)
  • Black clods (old)
  • Borders very sharply demarcated
  • Satellite clods, at some distance from the main lesion

Variants of seborrheic keratosis: Acanthotic type

Clues

  • White dots and/or clods
  • Yellow, brown, and/or orange clods
  • Brown circles, discrete
  • Thick brown lines, curved
  • Blue structureless zone
  • Border sharply demarcated
  • Vessels hairpin

Basal cell carcinoma

Clues

Blue clods varying in size and shape

  • Blue and gray dots
  • Peripheral lines radial, brown
  • Multiple foci of lines radial situated in the center of the lesion and converging to a central dot or clod
  • White structureless zone
  • Vessels branched
  • Orange structureless zone or orange clods
  • No lines reticular

Squamous-cell carcinoma, superficial (Bowen’s disease)

Clues

Multiple vessels as circles and spirals

2. Lesions melanocytic

Congenital nevi*

  • Blue nevus: “Common” blue nevus and “cellular” blue nevus
  • Combined congenital nevus (with a component of “blue nevus”)
  • Congenital nevus, superficial and superficial and “deep”
  • Unna’s nevus and Miescher’s nevus

* Not all of the many nevus variants are considered here

Congenital nevus, combined (with a component of “blue nevus”)

Clues

Variant #1:
Structureless blue zone, symmetric and well circumscribed (often situated centrally)

Variant #2:
Blue and brown clods, equal in size and shape

Congenital nevus, superficial and superficial and “deep”

Clues

Variant #1 (mainly reticular):
Colors light brown and dark brown, speckled often
Brown lines reticular dominate, lines branched and curved in part
Scattered brown dots or small clods occasionally
Brown circles

Variant #2 (mainly clods):
Brown clods, equal in size and shape

Variant #3 (reticular and clods):
Brown or skin-colored clods in the center
Lines reticular or lines branched at the periphery

Excessive terminal hairs may be a clue to all these types of congenital nevi

Congenital nevus: Unna’s nevus

Clues
Sparse light brown dots and clods
Yellow clods (infundibula filled with corneocytes)
Skin colored, structureless zone
Vessels curvilinear

Congenital nevi: Miescher’s nevus

Clues
Rectangular, brown, or skin colored clods
Yellow clods (infundibula filled with corneocytes)
Brown circles
Vessels curvilinear
Excessive terminal hairs

Acquired nevi

  • Spitz’s nevus
  • Reed’s nevus
  • Clark’s nevus

Spitz’s nevus

Clues
Brown clods at the periphery
Center structureless or clods white, gray, or blue
White or gray lines reticular in the center
Vessels as dots

Reed’s nevus
Clues
Lines radial or pseudopods, circumferential
Blue or black structureless zone in the center

Clark’s nevus
Clues
Variant #1 (mainly reticular):
Brown lines reticular
Central hyperpigmentation

Variant #2 (mainly dots/clods):
Small scattered brown dots or clods

Variant #3 (reticular and dots/clods):
Brown lines reticular
Dots and small clods in the center, at the periphery, or scattered throughout

Melanoma

Clues
White zone, structureless, asymmetric, and eccentric
Blue zone, structureless, poorly circumscribed, asymmetric, and eccentric
Black zone, structureless, asymmetric, and eccentric
Pink zone, structureless, poorly circumscribed, asymmetric, and eccentric
Gray dots and/or clods
Peripheral black dots and/or clods
Peripheral lines radial, segmental
Pseudopods
Thick lines reticular or thick lines branched
Combination of dotlike, linear, circular, and spiral vessels
Red or pink clods
Parallel ridge pattern
Multiple circles gray or black