Dermatoscopy of Benign Melanocytic Lesions

Question 1

What is the Global Structure of a Benign Melanocytic lesion?

Answer 1

Benign Melanocytic lesions have a well organised structure, they tend to be symmetrical, with uniform structure. They may be flat, flat peripherally and raised centrally, or entirely elevated.

Question 2

Describe the ‘wobble Sign’ and when it can be useful.

Answer 2

The wobble sign is when elevated naevi can be shifted using the dermatoscope. The ‘wobble sign’ may be useful to distinguish a papillomatous melanocytic naevus from a stable seborrhoeic keratosis.

Question 3

What is the predominant pattern of congenital naevi and childhood naevi? When does the network arise and why?

Answer 3

Predominant pattern of congenital naevi is Cobblestone pattern, Aggregated pattern is most predominant in childhood. A network arises in adolescents and adults presumably provoked by sun exposure. Naevi may then become homogeneous over time.

Question 4

Name this lesion and the structural pattern:

a) Cobblestone pattern (dermal naevi)
b) Aggregated globules
c) Pigment network (reticular pattern)
d) Homogeneous/amorphous (structureless) pigmentation

Answer 4

Benign Melanocytic Naevi

a) Cobblestone pattern

Question 5

Name this lesion and the structural pattern:

a) Cobblestone pattern (dermal naevi)
b) Aggregated globules
c) Pigment network (reticular pattern)
d) Homogeneous/amorphous (structureless) pigmentation

Answer 5

Benign Melanocytic Lesion-

Aggregated globules

Question 6

Name this lesion and the structural pattern:

a) Cobblestone pattern (dermal naevi)
b) Aggregated globules
c) Pigment network (reticular pattern)
d) Homogeneous/amorphous (structureless) pigmentation

Answer 6

Benign Melanocytic Lesion-

c) Pigment Network-Reticular pattern.

Question 7

Name this lesion and the structural pattern:

a) Cobblestone pattern (dermal naevi)
b) Aggregated globules
c) Pigment network (reticular pattern)
d) Homogeneous/amorphous (structureless) pigmentation

Answer 7

Benign Melanocytic lesion-

d) Amorphous (structureless) pigmentation

Question 8

Describe the name of this benign melanocytic naevus and what it is composed of?

Answer 8

This is a pointillist naevus, it is composed of multiple tiny brown or black dots on dermoscopy. It is uncommon.

Question 9

Describe the name of this benign melanocytic naevus and what it is composed of?

Answer 9

This is a pointillist naevus, it is composed of multiple tiny brown or black dots on dermoscopy. It is uncommon.

Question 10

Name this benign melanocytic naevi?

Answer 10

Blue Naevus-A uniform steel blue colour on dermoscopy. A cellular blue naevus, (buttocks), has pale or yellowish areas on the periphery and can resemble dermatofibroma. A combined naevus consists of a blue naevus in combination with a congenital, common, atypical or Spitz naevus.

Question 11

Name this benign melanocytic naevus?

Answer 11

Blue Naevus-A uniform steel blue colour on dermoscopy. A cellular blue naevus, (buttocks), has pale or yellowish areas on the periphery and can resemble dermatofibroma. A combined naevus consists of a blue naevus in combination with a congenital, common, atypical or Spitz naevus.

Question 12

Name this benign melanocytic naevus?

Answer 12

Blue Naevus-A uniform steel blue colour on dermoscopy. A cellular blue naevus, (buttocks), has pale or yellowish areas on the periphery and can resemble dermatofibroma. A combined naevus consists of a blue naevus in combination with a congenital, common, atypical or Spitz naevus.

Question 13

Name this benign melanocytic naevus?

Answer 13

Blue Naevus-A uniform steel blue colour on dermoscopy. A cellular blue naevus, (buttocks), has pale or yellowish areas on the periphery and can resemble dermatofibroma. A combined naevus consists of a blue naevus in combination with a congenital, common, atypical or Spitz naevus.

Question 14

Name the predominant colours of benign melanocytic lesions:

Answer 14

Black, Brown, Tan and Pink

Question 15

Name the Bengin Melanocytic Lesion and state the colour:

Answer 15

Compound Naevus-Black

Question 16

Name the Bengin Melanocytic Lesion and state the colour:

Answer 16

Junctional Naevus-Brown

Question 17

Name the Bengin Melanocytic Lesion and state the colour:

Answer 17

Cafe Au Lait Macule-Tan

Question 18

Name the Bengin Melanocytic Lesion and state the colour:

Answer 18

Dermal Naevus-Pink

Question 19

Describe the vascular pattern of a benign melanocytic lesion?

Answer 19

The vascular pattern of benign melanocytic naevi is often difficult to see. However, a uniform pattern of prominent blood vessels is often visible in skin coloured or pink dermal naevi; these may have hair pin appearance. The vessels are most often comma-like/peripheral but can be hairpin or arborising, which may result in confusion with basal cell carcinoma.

(see both Q & A pictures as an example)

Question 20

Describe the border of benign melanocytic lesions. What are 5 exceptions to this rule in relation to bengin lesions in particular?

Answer 20

Most benign melanocytic naevi have a border that gradually fades out with paler colour on the periphery

Ephelis: moth-eaten edge

Blue naevus: steel-blue uniform pigmentation

Pigmented Spitz naevus: peripheral globules are also often seen around a structureless centre

Reed naevus: ‘starburst’ pattern, circumferential radial streaming

Globular pattern of benign naevus

Question 21

Name this benign melanocytic lesion and describe it’s border.

Answer 21

Ephilis-Moth eaten border/edge.

Question 22

Name this benign melanocytic lesion and describe it’s border.

Answer 22

Reed Naevus. ‘Starburst’ pattern, circumferential radial streaming

Question 23

Name this benign melanocytic lesion and describe it’s border.

Answer 23

Spitz Naevus. Peripheral globules are seen around a structureless centre

Question 24

peripheral globules are also often seen around a structureless centre

Answer 24

Dermal Naevus. Globular pattern with sharp border and often elevated.

Question 25

What 3 flat benign melanocytic lesions are described as ‘freckles’?

Answer 25

1-Ephilis

2-Solar Lentigo

3-Lentigo Simplex

Question 26

Describe this naevus, and what would normally be seen under the Dermatoscope?

Answer 26

The Ephelis is a solar-induced macule with a normal number of melanocytes that produce increased melanin, which is distributed among keratinocytes. Dermoscopy of an ephelis generally shows uniform pigmentation and a moth-eaten edge.

Question 27

Describe this naevus, and what would normally be seen under the Dermatoscope?

Answer 27

The Ephelis is a solar-induced macule with a normal number of melanocytes that produce increased melanin, which is distributed among keratinocytes. Dermoscopy of an ephelis generally shows uniform pigmentation and a moth-eaten edge.

Question 28

Describe this naevus, and what would normally be seen under the Dermatoscope?

Answer 28

The Ephelis is a solar-induced macule with a normal number of melanocytes that produce increased melanin, which is distributed among keratinocytes. Dermoscopy of an ephelis generally shows uniform pigmentation and a moth-eaten edge.

Question 29

Describe this naevus, and what would normally be seen under the Dermatoscope?

Answer 29

The Ephelis is a solar-induced macule with a normal number of melanocytes that produce increased melanin, which is distributed among keratinocytes. Dermoscopy of an ephelis generally shows uniform pigmentation and a moth-eaten edge.

Question 30

Describe this naevus, and what would normally be seen under the Dermatoscope?

Answer 30

The lentigo simplex has increased melanocytes producing increased melanin. Dermoscopy characteristically shows a dark uniform network across the whole lesion. Very dark lesions are known as ink spot lentigos. Blue pigmentation occurs in some lesions due to dermal melanophages.

Question 31

Describe this naevus, and what would normally be seen under the Dermatoscope?

Answer 31

The lentigo simplex has increased melanocytes producing increased melanin. Dermoscopy characteristically shows a dark uniform network across the whole lesion. Very dark lesions are known as ink spot lentigos. Blue pigmentation occurs in some lesions due to dermal melanophages.

Question 32

Describe this naevus, and what would normally be seen under the Dermatoscope?

Answer 32

The lentigo simplex has increased melanocytes producing increased melanin. Dermoscopy characteristically shows a dark uniform network across the whole lesion. Very dark lesions are known as ink spot lentigos. Blue pigmentation occurs in some lesions due to dermal melanophages.

Question 33

Describe this naevus, and what would normally be seen under the Dermatoscope?

Answer 33

The lentigo simplex has increased melanocytes producing increased melanin. Dermoscopy characteristically shows a dark uniform network across the whole lesion. Very dark lesions are known as ink spot lentigos. Blue pigmentation occurs in some lesions due to dermal melanophages.

Question 34

Describe this naevus, and what would normally be seen under the Dermatoscope?

Answer 34

The solar lentigo is a solar-induced macule with solar elastosis, elongated rete ridges and a normal number of melanocytes producing increased melanin. They may evolve into seborrhoeic keratosis. Dermoscopy of a solar lentigo may show a faint pigmented network or fingerprint structures or uniform pigmentation.

Question 35

Describe this naevus, and what would normally be seen under the Dermatoscope?

Answer 35

The solar lentigo is a solar-induced macule with solar elastosis, elongated rete ridges and a normal number of melanocytes producing increased melanin. They may evolve into seborrhoeic keratosis. Dermoscopy of a solar lentigo may show a faint pigmented network or fingerprint structures or uniform pigmentation.

Question 36

Describe this naevus, and what would normally be seen under the Dermatoscope?

Answer 36

The solar lentigo is a solar-induced macule with solar elastosis, elongated rete ridges and a normal number of melanocytes producing increased melanin. They may evolve into seborrhoeic keratosis. Dermoscopy of a solar lentigo may show a faint pigmented network or fingerprint structures or uniform pigmentation.

Question 37

Describe this naevus, and what would normally be seen under the Dermatoscope?

Answer 37

The solar lentigo is a solar-induced macule with solar elastosis, elongated rete ridges and a normal number of melanocytes producing increased melanin. They may evolve into seborrhoeic keratosis. Dermoscopy of a solar lentigo may show a faint pigmented network or fingerprint structures or uniform pigmentation.

Question 38

Congenital melanocytic naevi may be recognised dermatoscopically by the following features: (8)

Answer 38

1-Frequently, large size and asymmetrical shape

2-Terminal hairs

3-Cobblestone/globular or homogenous pattern or multicomponent pattern

4-Black or brown dots and globules

5-Milia-like cysts

6-Crypts and fissures

7-Up to 4 colours (uniformly scattered, central hypopigmentation or central hyperpigmentation)

8-Congenital Melanocytic Naevi often have prominent symmetric hypopigmented areas.

**Presence of asymmetry, multiple colours, and multicomponent pattern on dermoscopy may indicate melanoma. History of change within the lesion should be taken seriously as melanoma may arise in congenital melanocytic naevi, especially in giant naevi.

**Pictures indicate homogenous pattern and crypts.

Question 39

Congenital melanocytic naevi may be recognised dermatoscopically by the following features: (8)

Answer 39

1-Frequently, large size and asymmetrical shape

2-Terminal hairs

3-Cobblestone/globular or homogenous pattern or multicomponent pattern

4-Black or brown dots and globules

5-Milia-like cysts

6-Crypts and fissures

7-Up to 4 colours (uniformly scattered, central hypopigmentation or central hyperpigmentation)

8-Congenital Melanocytic Naevi often have prominent symmetric hypopigmented areas.

**Presence of asymmetry, multiple colours, and multicomponent pattern on dermoscopy may indicate melanoma. History of change within the lesion should be taken seriously as melanoma may arise in congenital melanocytic naevi, especially in giant naevi.

**Pictures indicate terminal hairs and cobblestone pattern

Question 40

What are the most common sites for mucosal melanosis and what is the appearance under dermatoscope?

Answer 40

Benign melanosis of mucosal surfaces (lips, vulva, penis) is relatively featureless on dermoscopy showing uniform amorphous pigmentation.

Question 41

Where exactly is pigment distributed in benign naevi on palms and soles? Name 5 pigmentation patterns of these naevi and name the pattern in the picture shown.

Answer 41

• Pigment is distributed in the furrows of palm and sole naevi.
• Pigmentation patterns can be described as:

1-Parallel

2. Fibrillar or Filamentous

3- Lattice-type

4. Homogenous.
5. Globular

Question 42

Where exactly is pigment distributed in benign naevi on palms and soles? Name 5 pigmentation patterns of these naevi and name the pattern in the picture shown.

Answer 42

• Pigment is distributed in the furrows of palm and sole naevi.
• Pigmentation patterns can be described as:

1-Parallel

2. Fibrillar or Filamentous

3- Lattice-type

4. Homogenous.
5. Globular

Question 43

Where exactly is pigment distributed in benign naevi on palms and soles? Name 5 pigmentation patterns of these naevi and name the pattern in the picture shown.

Answer 43

• Pigment is distributed in the furrows of palm and sole naevi.
• Pigmentation patterns can be described as:

1-Parallel

2. Fibrillar or Filamentous

3- Lattice-type

4. Homogenous.
5. Globular

Question 44

Where exactly is pigment distributed in benign naevi on palms and soles? Name 5 pigmentation patterns of these naevi and name the pattern in the picture shown.

Answer 44

• Pigment is distributed in the furrows of palm and sole naevi.
• Pigmentation patterns can be described as:

1-Parallel

2. Fibrillar or Filamentous

3- Lattice-type

4. Homogenous.
5. Globular

Question 45

Describe the ‘pseudonetwork’ which often characterises lesions on the face, and what may give away a Seb K in this location.

Answer 45

Pseudonetwork describes a broad annular pattern of pigmentation around numerous and prominent hair follicles. The pseudonetwork in benign lesions is symmetrical and regular. Some solar lentigines do not have pseudonetwork and are uniformly amorphous; the flat seborrhoeic keratosis with dry or scaly surface may reveal white reflected or dull yellow keratin.

**Solar Lentigo on the face (1st image)

**Seb K on the face (2nd image)

Question 46

Describe the appearance of a benign naevi on the nail, both clinically and under Dermatoscope.

Answer 46

Benign naevi may result in one or more parallel longitudinal bands of pigment on the nail plate. On dermoscopy, the colour is uniform and equal in diameter at the proximal and distal ends of the band, which may arise within a pale brown background. Naevi may be congenital, in which case there may be some variation in thickness and colour of the pigmented bands. A uniformly pale brown nail may be a lentigo.

Question 47

Name this benign melanocytic naevi, describe it clinically and Dermatoscopically, and describes the reason for the colour features.

Answer 47

Halo naevi fade away because of an immune reaction. Clinically the mole is surrounded by hypopigmentation or achromia. Dermoscopy shows symmetrical peripheral hypopigmentation without scarring. The central naevus may be typical or atypical, fully developed or fading away. Globular and homogeneous patterns may be seen. Evolving halo naevi may slowly disappear over months to several years.

The pseudohalo naevus is a normal mole that has been protected from sun exposure, e.g., with sunscreen or a plaster, preventing tanning of the skin adjacent to the lesion. The mole in the middle is of normal structure and does not evolve.