Harald's Algorithm

INTRODUCTION TO PATTERN ANALYSIS MODIFIED BY KITTLER

2009-07-19T20:25:00.002+10:00

Use the Labels opposite to use the Algorithm

Several algorithms and systems have been devised to diagnose skin lesions, particularly pigmented skin lesions.
As these systems have evolved terminology has been accumulated to describe structures seen through the dermatoscope. The terminology has in the past often been metaphorical.
There are terms like ovoid nests, lagunes, lacunes, globules, leaf-like structures,maple leaf like structures, spoke-wheels, radial streaming, blue-white veil, peppering, fat fingures, sulci-gyri, crypts, milia-like cysts, arborosing vessels, etc etc. Often there are no precise definitions of these terms. Also, metaphorical terms have emotional connotations. That means that the meaning evoked for one person may be different to that evoked for another.

A Metaphoricoma

The Pattern Analysis modified by Kittler has simple defined terms for basic structures.
All structures can be described using the following 5 terms
Lines (Reticular, branched, curved, radial, parallel)
Dots
Clods
Circles
Pseudopods
Areas with none of the above are termed "structureless"

All patterns can be described as combinations of these structures
ALL OF THE STRUCTURES ARE ILLUSTRATED BELOW. THERE ARE NO OTHERS TO REMEMBER!

There are 2 parts to the Kittler algorithm

1. To Diagnose a Melanoma
2. Algorithm for Specific Diagnosis

The "To Diagnose a Melanoma" algorithm is arguably the simplest and most effective algorithm devised
If there is one pattern and one colour you move to the next lesion because that lesion is benign.
If there is more than one pattern OR more than one colour then you look for one of 8 "clues to melanoma". The discovery of just one clue may mandate the need for appropriate biopsy.
The clues are as follows
1. Eccentric structureless zone (any colour except skin colour)
2. Grey dots, clods, circles or lines
3. Black dots or clods, peripheral
4. Lines radial or pseudopods, segmental
5. Serpentine, helical and/or coiled vessels
6. White lines
7. Thick lines reticular or branched
8. Lines parallel, ridges

What about exceptions to the rule? What about nodular or amelanotic melanomas with one pattern and one colour?
Harald has stated categorically that his algorithm is not meant to be robotic. Everybody is encouraged to make his own modifications and develop his own algorithm.

I apply two principles whenever assessing skin lesions which override all other algorithmic decisions
1. If the lesion is EFG positive I biopsy it ( Elevated, Firm, Growing)
2. The "AORAKI" principal - If I can't make a CONFIDENT SPECIFIC BENIGN diagnosis I biopsy it (this is where the 2nd part of the Kittler algorithm is important. It is a tool for making a SPECIFIC benign diagnosis)

These two principles have yielded me amoung other things a Merkel cell carcinoma, an amelanotic melanoma, a nodular melanoma and several SCC,s that looked like seborrhoeic keratoses.

The second part of the Kittler algorithm "The Algorithm for Specific Diagnosis" is an elaborate systen for stepwise evaluation of lesions to identify them specifically ( not just as benign or suspicious). That is all condensed onto one poster available as a PDF file on this blog. You will need to have it printed at at least A3 size to read it as it represents 62 web pages condensed to one page.
This algorithm is not meant to be learned in one day! It is "complex but simple". It "falls together" when applied logically. Put the poster where you can refer to it often.

The Kittler method of describing vessels is based on the same simple principles with defined precise terminology that can be used to describe all vessels encountered.
Vessels can be
dots
clods
Lines straight
Lines looped
Lines curved
Lines serpentine
Lines helical
Lines coiled

and they can have patterns :-
Random pattern
Clustered
Serpiginous
Radial
Reticular
Branched

DEFINITIONS

Dots are tiny round spots not extending in any direction (no length and no breath)
Clods are well circumscribed, solid objects larger than dots that may take any shape (length and breath)
Lines are 2-dimensional continuous geometric figures extending in one direction (only length but no breath)
A Circle is a curved line equidistant from a central point
A Pseudopod is a line with a bulbous end

With Respect to Vessels

Linear vessels without a bend are straight.
Linear vessels with only one bend are looped if the bend is sharp (180°) and results in a reversal of direction (U-turn)
Linear vessels are curved if the bend is gentle.
Linear vessels with more than one bend are termed serpentine if the bends are arranged in a snakelike fashion
Linear vessels are Helical if the bends are twisted along a central axis
Linear vessels are Coiled if the bends are convoluted compactly (Figure 1).

Harald's own definitions are as follows.
straight= no bend
looped= one bend, 180 degrees
curved= one bend, less than 180 degrees
Serpentine= much more than one bend, any degree, not convoluted compactly
Coiled=more than one bend, convoluted compactly
Spiral= more than one bend, not convoluted compactly but convoluted along a central axis

The additional attributes thin and thick may be applied to all types of linear vessels. The attribute thick should only be applied if the thickness of the vessels exceeds the diameter of normal nail fold capillaries by far.
If one type of vessel is dominating by far the vascular pattern is termed monomorphic. If there are more than one type of vessel the pattern is termed polymorphic.
As a rule, a pattern is formed by multiple vessels that appear to be distributed in a random fashion and are not arranged in a specific way. However, it is important to note that there are some exceptions
If vessels that appear as dots or coiled vessels are not evenly distributed but concentrated in certain areas we call this pattern clustered.
If vessels that appear as dots or coiled vessels are arranged in a linear, arciform pattern we call that specific arrangement serpiginous ( eg Clear Cell Acanthoma)
Linear vessels (of the type straight, curved or looped) at the periphery that are orientated towards the centre of the lesion but are not crossing it are termed radial ( eg sebaceous hyperplasia and keratoacanthoma)
Linear straight vessels may cross each other and may be arranged in a way similar to pigmented lines reticular. We therefore call this vascular pattern reticular ( eg variant of mastocytosis known as telangiectasia macularis perstans)
Multiple serpentine vessels may divide from a main stem (usually a thick serpentine vessel), a pattern which is termed branched.

FINALLY - If Alan can do it it can't be that difficult...

"Sie haben eine Methode vor dem blinkenden!"

See the Labels opposite top to access the Algorithm

I have condensed Harald's entire algorithm ( all 62 Web pages) onto a single poster. You can go to http://www.skincancerconsult.com/ to the Presentations section under Word and PDF files -you will need to obtain a username and password from Ian McColl (imccoll@ozemail.com.au)- and download the PDF of the poster. Alternatively email me at cliffr@qld.chariot.net.au and I will happily send you the PDF file. It needs to be printed out at least on A3 paper, preferably glossy photo paper.

This algorithm is totally up to date. After Harald emailed me the changes he sent the following message:-

"The algorithm looks great. Thank you again for your work. I personally will not make any additional changes. Now its up to everybody out there to test it, change it, tear it apart, put it together again, and to add, remove,and change diagnoses."

Lines.

2008-10-28T07:01:00.004+10:00

Case 1, Woman 60's; 6mm diameter, mid back.

Case 2, Woman 70's, 12mm diameter, calf
More practice cases for Harald's algorithm. We look at lines today.

Clods

2008-10-27T20:16:00.000+10:00

Forehead

Neck

These cases are posted for those who wish to practice the "Diagnosis Accurate" Kittlerian algorithm. That is the long algorithm on the poster that is available from me at cliffr@qld.chariot.net.au

Please do your analysis stepwise following either the "one pattern" or "more than one pattern" arm of the algorithm as appropriate. I will post the answers in a few days. If you want them earlier send me an email.

Alan and I will respond to any questions you ask to the best of our ability. Harald may also respond when possible.

The Analysis

2008-07-12T07:20:00.020+10:00

This is a trial website to work out how best to illustrate Harald Kittler's algorithm for dermatoscopic diagnosis. There are links under the relevant diagnostic trees to sections of www.dermoscopyatlas.com where we hope to have examples of each of the diagnostic features but this will take a little while to populate. Many thanks to Harald for allowing us to copy some of his artwork.

1.

2

For more than one pattern go to this post.

If one pattern choose the pattern from the algorithm path below. Lines take precedence over the others with pseudopods next and the others in the sequence below with structureless last!

3

4 If lines reticular (net like) then look at colour and thickness.

1 Pattern Reticular 1 Colour

Thin and brown Solar lentigo , Clark nevus
Thick and brown Reticulate seborrhoeic keratosis Clark nevus Congenital nevus superficial
Black Ink spot lentigo (1) Reed nevus

5 Lines reticular with more than one colour. If any black eccentric (ie at the edges) think of melanoma.

1 Pattern Reticular more than 1 Colour

Dark brown or black centric Clark nevus
Dark brown and light brown speckled Congenital nevus superficial Nevus spilus Clark nevus Solar lentigo
Dark brown or black eccentric Clark nevus Melanoma in situ
Variegate Congenital nevus superficial Clark nevus Melanoma in situ
6

7

8 One pattern, Lines branched usually brown or black. The Ink spot lentigo is the easiest to recognise.

1 Pattern Branched

Branched Brown Congenital nevus Clark nevus
Branched Black Ink spot lentigo
9

10 One pattern, Lines parallel. Check to see if in the ridges or furrows. Remember haemorrhage can give a parallel ridged pattern and not just melanoma!

1 Pattern Parallel

Ridges Brown Melanoma in situ Acral nevus Melanotic macule
Ridges Black, purple and red Hemorrhage Exogenous pigmentation
Parallel Furrows Acral nevus
Parallel perpendicular to ridges Acral nevus
11

12 One pattern, Lines radial. Here if peripheral , are they all the way round or only part of the way? If within a lesion then it is the Kittlerian description of the spoke wheel sign in a BCC

1 Pattern Radial

Radial peripheral circumferential Reed nevus
Radial peripheral segmental Melanoma Basal cell carcinoma
Radial central and multifocal Basal cell carcinoma (1)
13

14 One pattern, Lines curved Solar lentigo or early flat seborrhoeic keratosis.

1 Pattern Curved

Lines Curved Solar lentigo
15

16 One pattern, Pseudopods. If definite then even a couple of pseudopods can mean a melanoma. Usually peripheral but not always. Sometimes within a lesion where a melanoma is starting.

1 Pattern Pseudopods

Pseudopods circumferential Reed nevus
Pseudopods segmental Melanoma
17

18 One pattern, Circles. Usually all about the colour. Gray circles are the ones to watch out for as they mean either melanoma, LPLK , Pigmented solar k or Pigmented IEC (Bowens)

1 Pattern Circles

Circles 1 colour brown Seborrhoeic keratosis Dermatofibroma Solar lentigo Clark nevus
Circles 1 colour red Solar keratosis
Circles > 1 colour brown and or yellow Seborrhoeic keratosis
Circles > 1 colour Gray or black in part Melanoma in situ LPLK Pigmented solar keratosis
19

20 One pattern, Clods. Again all about colour

21

1 Pattern Clods 1 Colour

Clods 1 colour Red Hemangiomas Vascular malformations Hemorrhage fresh in Stratum corneum
Clods 1 colour Purple Hemangioma Vascular malformations
Clods 1 colour Orange Basal cell carcinoma Seborrhoeic keratosis
Clods 1 colour Yellow and or White Seborrhoeic keratosis
Clods 1 colour Skin coloured Congenital nevus Unna or Miescher nevus Seborrhoeic keratosis acanthotic
Clods 1 colour Brown Congenital nevus superficial and deep Spitz nevus Unna or Meischer nevus
Clods 1 colour Black Hemangioma thrombosed Hemorrhage old in stratum corneum
Clods 1 colour Blue Basal Cell carcinoma (1)
22

1 Pattern Clods with more than 1 Colour

Clods >1Colour Yellow or white dominant Seborrhoeic keratosis
Clods >1colour Orange dominant Basal cell carcinoma Seborrhoeic keratosis
Clods >1colour Red or purple dominant Hemangiomas Vascular malformations

Clods >1colour Melanin dominant Colours symmetric Congenital nevus superficial and superficial and deep
Clods >1colour Melanin dominant Colours asymmetric Basal cell carcinoma Melanoma

23

24 One pattern, Dots. Again colour but watch for the gray dots which indicate LPLK, Pigmented solar k, or regressed melanoma. Dots as lines are also a feature of Pigmented IEC.

1 Pattern Dots (Look at the colour)

Dots Gray LPLK Pigmented solar keratosis Melanoma Pigmented Bowen's disease (pIEC)
Dots Brown Clark nevus Pigmented Bowen's disease (pIEC)
Dots Red Clark nevus Clear cell acanthoma Bowen's disease (IEC) Inflammatory process eg Psoriasis
25

26 One pattern, Structureless. Not very specific of anything but go on the colour. Blue nevus is probably the best example of the genre!

27

1 Pattern Structureless 1 Colour

Structureless 1 colour Black Hemorrhage old Hemangioma thrombosed
Structureless 1 colour Blue Blue nevus
Structureless 1 colour Red Hemorrhage fresh

Rarely melanocytic lesions (Clark nevus, Reed nevus, Melanoma) can be black and structureless)
28

1 Pattern Structureless > 1 Colour

Structureless >1colour White yellow or orange dominant Seborrhoeic keratosis acanthotic Basal cell carcinoma Amelanotic melanoma
Structureless >1colour Red dominant Hemorrhage fresh

Structureless >1colour Melanin dominant Colours symmetric Congenital nevus superficial Congenital nevus combined Blue nevus Clark nevus Spitz nevus Reed nevus
Structureless >1colour Melanin dominant Colours asymmetric Melanoma primary Melanoma metastatic

More than one pattern

2008-07-11T08:46:00.013+10:00

Text here
1

2

3

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5

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9

10

11

Patterns asymmetric 1colour Brown Clark nevus Congenital nevus superficial

Patterns asymmetric >1colour Melanoma clue present Melanoma
Patterns asymmetric >1colour Melanoma clue absent Clark nevus Congenital nevus superficial Congenital nevus combined
12

13

Parallel ridges pigment other than melanin Hemorrhage Exogenous pigmentation
Parallel ridges pigment melanin 1colour brown Melanoma in situ Acral nevus Melanotic macule
Parallel ridges pigment melanin >1colour Melanoma

Parallel furrows or crossing ridges and furrows Acral nevus
14

15

Lines radial peripheral circumferential centre white or light brown Dermatofibroma
Lines radial peripheral segmental Melanoma Basal cell carcinoma

Lines radial central Basal cell carcinoma
16

17

Pattern lines curved Solar lentigo Seborrhoeic keratosis Congenital nevus superficial
18

19

Pattern Pseudopods circumferential Reed nevus

Pattern Pseudopods segmental Melanoma
20

21

Pattern Circles brown Seborrhoeic keratosis variants Congenital nevus superficial Miescher nevus Dermatofibroma Clark nevus

Pattern Circles gray or black in part Melanoma LPLK Pigmented solar keratosis Pigmented IEC
22

23

24

25

Patterns asymmetric Clods yellow and or white Seborrhoeic keratosis (1)
Patterns asymmetric Clods orange Basal cell carcinoma
Patterns asymmetric Clods red and or purple Hemangiomas Vascular malformations Melanoma primary Melanoma metastatic

Patterns asymmetric Clods melanin 1colour brown Congenital nevus superficial Spitz nevus
Patterns asymmetric Clods melanin >1colour Basal cell carcinoma Melanoma Seborrhoeic keratosis and variants
26

27

Patterns Dots gray LPLK Pigmented solar keratosis Pigmented Bowen's disease (pIEC) Melanoma Basal cell carcinoma
Patterns Dots blue Basal cell carcinoma
Patterns Dots black Melanoma Clark nevus
Patterns Dots brown Clark nevus Congenital nevus superficial Solar lentigo Pigmented Bowen's disease (pIEC)

Vessels

2008-07-06T21:07:00.017+10:00

1 Morpholgy of vessels

Vessels Dots Melanocytic lesions, Amelanotic melanoma, Psoriasis, Stasis dermatitis

Vessels Clods Basal cell carcinoma (1) Hemangiomas

Vessels Lines, straight

Vessels Lines, looped Seborrhoeic keratoses, SCC, Keratoacanthoma

Vessels Lines, curved Dermal nevi, Congenital nevi,

Vessels Lines, convoluted BCC

Vessels Lines, serpentine Many lesions BCC

Vessels Lines, helical Melanoma

Vessels Lines, coiled SCC in situ (1) (2) Rarely Seborrhoeic keratoses

2 Arrangement of vessels

Arrangement, no specific arrangement

Arrangement, clustered

Arrangement, serpiginious Clear cell acanthoma

Arrangement, radial Sebaceous hyperplasia, Keratoacanthoma

Arrangement, reticular

Arrangement, branched Particularly BCC, Keratoacanthoma (1) Dermal nevi, Rapidly growing tumours

Definition of vessels
straight= no bend
looped= one bend, 180 degrees
curved= one bend, less than 180 degrees
Serpentine= much more than one bend, any degree, not convoluted compactly
Coiled=more than one bend, convoluted compactly
Spiral= more than one bend, not convoluted compactly but convoluted along a central axis

Description of vessels:

1. Monomorphic or polymorphic
Monomorphic= a single type of vessel dominates by far=1 pattern
Polymorphic= more than one type of vessel => 1 pattern (Dot and helical Melanoma)

2. Which type of vessel?

3. Arrangement of vessels?

4. Descriptive modifiers that may be used:
thin-thick (thick=thicker than normal nail fold capillaries)
short-long (long= crossing a significant part of the lesion)
Modifiers should be used rarely and only for obvious abberations from "normal"

Descriptive definitions

2008-07-06T19:38:00.002+10:00

Click on the Block space to view Harald's descriptive definitions of terms.

Questions for the Authors

2008-07-05T06:37:00.000+10:00

Use this section to ask questions of the authors about any areas of difficulty you are having with Harald's Algorithm and we will try to answer them. Just pose your question as a Comment by clicking the Comment box and type in your question. It will be automatically sent to each of the authors, one of whom should answer shortly.