2 Step Algorithm

Question 1

What are the FIRST 1-3 / 9 components of a melanocytes lesion?

Answer 1

1 - Pigment Network 2- Negative Network 3- Polygonal Lines

Question 2

What are the SECOND 4-6 /9 components of a melanocytic lesion?

Answer 2

3- Aggregated Globules 4- Peripheral Rim of Globules 5- Streaks

Question 3

What are the THIRD 7 - 9 components of a melanocytic lesion?

Answer 3

1- Homogeneous Blue Pigment 2- Pseudo Network (facial skin) 3- Parallel Pigment Pattern (Palms, Soles & Nails)

Question 4

Honeycomb-like, reticular, web-like line segments (elongated and hyperpigmented rete ridges) with hypopigmented holes (dermal papillae).

Answer 4

Pigment network

Question 5

The 2-step dermoscopy rule does have a few exceptions; the most common one being:

Answer 5

dermatofibroma

Question 6

Dermatofibroma is not a melanocytic lesion but it does often reveal a:

Answer 6

network

Question 7

Other exceptions to The 2-step dermoscopy rule may also include:

Answer 7

lentigines and seborrheic keratoses.

Question 8

The most common exception to including lesions with pigment network in the melanocytic category is the:

Answer 8

dermatofibroma: in which the pattern of a peripheral network combined with central scar-like area trumps categorizing the lesion as melanocytic.

Question 9

Describe the appearance of a dermatofibroma

Answer 9

A pattern of a peripheral network combined with central scar-like area trumps categorizing the lesion as melanocytic.

Question 10

Describe the 4 components of a dermatofibroma.

Answer 10

1- A firm papule that 2- dimples on pressure and 3- has a central scar like area with 4- and has a peripheral delicate pigment network.

Question 11

If the lesion is deemed not of melanocytic origin then one needs to look for structures seen in 5 different dermal lesions: List the 5 options

Answer 11

1- Dermatofibromas 2- Basal cell carcinomas 3- Squamous cell carcinomas 4- Seborrheic keratoses 5- Hemangiomas

Question 12

Dermatofibromas have the 4 following characteristics:

Answer 12

1- Peripheral delicate fine network 2- Central white to pink scar-like area with or without crystalline structures 3- Vessels/pink blush in center 4- Ring-like globules

Question 13

Basal cell carcinomas have the following 11 characteristics:

Answer 13

1- Arborizing vessels (tree-like telangiectasia) 2- Spoke-wheel-like structures 3- Leaf-like areas 4- Large blue-gray ovoid nest 5- Multiple blue-gray non-aggregated globules 6- Ulceration 7- Shiny white structures (crystalline structures consisting of lines and clods) 8- Multiple brown/blue-gray dots (sharply in focus) 9- Concentric structure (considered a variant of spoke-wheels) 10- Short fine telangiectasia 11- Multiple erosions (serous crust) The other features, while not diagnostic of BCC, provide additional clues confirming the diagnosis: shiny white structures seen with polarized light, dots, short fine vessels and concentric structures.