Dermatoscopic structures of non-melanocytic lesions

Question 1

Name this feature accentuated with the arrow, where are they commonly present?

Answer 1

These are Dots, they may be seen in pigmented BCCs and rarely Seborrhoeic Keratoses.

Question 2

What are 4 dermatoscopic structures that are helpful in non-melanocytic lesions?

Answer 2

Leaf-like areas

Blue ovoid masses

Milia-like cysts

Fissures and comedo-like openings.

Question 3

What dermatoscopic feature is seen in this lesion?

Answer 3

Structureless, Leaf-like areas. Grey, brown or blue structures unassociated with a pigment network (structureless). Seen on the edges of pigmented BCC, when they often have darker areas within them (blue ovoid masses).

Question 4

What dermatoscopic feature is seen in this picture?

Answer 4

Blue Ovoid mass

Large discrete pigmented blue structures. Characteristic of BCC. When the structure has radial projections, they are called ‘spoke-wheel areas’. Often found within leaf-like/structureless areas. Blue blotches that are sometimes seen in melanoma are irregular, less well defined and appear out of focus.

Question 5

What dermatoscopic feature is seen in this compound naevus?

Answer 5

Milia

Round white or yellow lesions due to intraepidermal keratin. Characteristically found within a seborrhoeic keratosis. They may also arise within dermal melanocytic naevi, BCC and melanoma.

Question 6

What dermatoscopic feature can be seen in this Seb K?

Answer 6

Comedo-like openings are also called ‘crypts’. They are often associated with fissures (clefts). Characteristic of seborrhoeic keratoses, but may also be found in dermal naevi. Rarely found in melanoma.

Question 7

What dermatoscopic feature can be seen in this Seb K?

Answer 7

A seborrhoeic keratosis may have a cerebriform or brain-like pattern. The pattern is composed of fissures and ridges mimicking the gyri and sulci of the brain.

Question 8

What dermatoscopic feature can be seen in this naevus?

Answer 8

Finger-like Structures

A descriptive term for tan or dark-brown, fine parallel cord-like structures often seen in seborrhoeic keratoses and solar lentigo. Wider cords are called ‘fat fingers’. Fat fingers are also rarely seen in melanoma.

Question 9

Describe 2 dermoscopic features of Haemangiomas or Angiomas

Answer 9

1-Widespread red-blue lacunes

2-Red-bluish-black homogeneous areas

Question 10

Describe the border of this lesion and the white structures present. What can cause this lesion and what is the most important DDx?

Answer 10

• A distinct keratinised border or collarette (can also be present in Pyogenic Granuloma).
• White linear ‘rail lines’ are often featured.
• Amelanotic melanoma must be a differential diagnosis

Question 11

Name this vascular lesion and describe 4 characteristics

Answer 11

Kaposi Sarcoma

1-Multicolour Rainbow Pattern

2-Bluish-red colour

3-Scaling

4-Small brown globules

NB: Rainbow pattern occasionally seen in melanoma and other skin lesions.

Question 12

How can haemorrhage be distinguished from pigmentation due to melanin with dermoscopy?

Answer 12

Haemorrhage can be distinguished by the purple colour

Question 13

Describe this lesion and it’s name

Answer 13

This is Talon Noir on the plantar surface

• It may appear to have a parallel ridge pattern of discolouration with peripheral reddish-black globules.
• Talon noir is also called ‘black heel’ or calcaneal petechiae, talon noir is considered to be induced by trauma.

Question 14

What is an easily recognisable clinical characteristic of Dermatofibroma (aka Histiocytoma)?

What does dermoscopy of a dermatofibroma typically show?

Answer 14

Firm fibrous consistency and surface dimpling on compression

• A faint network or pseudonetwork surrounding a pale amorphous area.
• Sometimes the central white area has white lines and brown holes (negative network).
• Chrystalline structures, i.e. white shiny lines, are commonly seen on polarised dermoscopy of dermatofibroma.

NB: Rarely, a rainbow pattern can be observed.

Question 15

Name and describe this uncommon type of dermatofibroma

Answer 15

Haemosiderotic dermatofibroma

• Composed of numerous small vessels, extravasated erythrocytes and intra- and extracellular haemosiderin deposits.
• Dermoscopy reveals multicomponent pattern with a central bluish or reddish homogeneous area in combination with white or yellowish structures and a peripheral delicate pigment network.

Question 16

Give a clinical description of Neurofibroma and describe the sign that can help differentiate from the another skin condition it is often confused with.

Give a short Dermoscopic Description

Answer 16

Clinically Neurofibromas are soft to firm papules or nodules.

The buttonhole sign is helpful: you can push the lesion through a defect in the dermis and it bounces back when pressure is removed. This can differentiate it from a dermal naevus or skin tag.

Dermoscopically, Neurofibroma is a featureless nodule.

Question 17

Define Lichenoid Keratosis

Describe it’s activity ata cellular level and how this gives the lesion its colour

Describe the pigment network in Lichenoid Keratosis

Answer 17

Lichenoid keratosis is an inflammatory reaction arising in a regressing existing solar lentigo or seborrhoeic keratosis.

• Localised destruction of melanocytes and free melanin in the dermis or melanin within melanophages. These appear as granular areas of grey dots. Grey dots can also be typically seen within melanoma.
• LK has no pigment network and there are usually amorphous areas with or without keratinous surface /or other features of seborrhoeic keratosis.

Question 18

Describe Porokeratosis and it’s Dermatoscopic characteristics

Answer 18

Porokeratosis is distinguished by a cornoid lamella (horn-like thin layer) around the lesion. Sometimes there is prominent follicular plugging

Question 19

Describe the dermatoscopic appearance of sebaceous hyperplasia and how the vascularity differs from BCC

Answer 19

Sebaceous hyperplasia is distinguished by pale yellow lobules around a central follicular opening. Telangiectasia is common but tends to be uniform, in contrast to the irregular arborising vessels seen in basal cell carcinoma.

Question 20

Describe the different dermatoscopic features of viral warts, corns and a callus

Answer 20

Viral warts are keratinocytic lesions with a lobular structure, sometimes with a central thrombosed capillary within each lobule. The normal dermatoglyphics are interrupted. Some have a papilliform structure.

In contrast, a corn has a translucent central core, and a callus is hyperkeratotic without other distinguishing features.

Question 21

Describe Epidermal Naevus and how it differs from a Seborrhoeic Keratosis

Answer 21

An Epidermal Naevus has fissures, crypts and milia.

-It resembles a seborrhoeic keratosis or viral wart, however differs because it is very uniform in appearance and appears within the first decade.

Question 22

Describe the dermoscopy of the nipple

Answer 22

Breast tissue has a delicate uniform peripheral pigment network.

Question 23

Describe this pigmentation pattern on normal areola

Answer 23

Delicate uniform peripheral pigment network

Question 24

What is the main dermatoscopic feature of a cyst?

Answer 24

Central follicular opening

Question 25

Describe the dermoscopic features of Clear Cell Acanthoma

Answer 25

Clear Cell Acanthoma is a benign epidermal tumour. There are multiple pinpoint or dotted vessels arranged in line like a string of pearls.

Question 26

Describe the dermatoscopic features of Trichoepithelioma/Trichoadenoma

Answer 26

Multiple white clods of variable diameter ( milia like cysts )

Question 27

Describe the vascular pattern in the below lesions with red scaly plaques:

1-Amelanotic melanoma:

2- Superficial basal cell carcinoma:

3-Squamous cell carcinoma in situ:

4-Psoriasis:

5-Lichen planus:

Answer 27

1-Atypical and polymorphous vascularity

2-Arborising telangiectasia, ulceration

3-Grouped glomerular vessels

4-Uniform distribution of red dots on a light pink homogeneous background

5-White Wickham’s striae, paucity of vessels

Question 28

Describe the Dermoscopy (entodermoscopy) of Scabies, nits and cutaneous larvae migrans (hookworm)

Answer 28

Scabies-Identify a scabies mite and/or its faeces within its burrow (triangle shaped head)

Nits-Confirm the presence of nits gripping a hair shaft in pediculosis capitis

Cutaneous larvae migrans-2–3 mm-wide, snakelike tracks stretching 3–4 cm from the penetration site. These are slightly raised, flesh-coloured or pink

Question 29

What 4 main characteristics do Seb Ks have?

Answer 29

1-Multiple milia-like cysts

2-Comedo-like openings

3-Light-brown fingerprint-like structures

4-Cerebriform pattern