Porokeratosis (Mibelli)

A 63-year-old woman consulted for this brown-red annular plaque on her right leg. This lesion had been slowly expanding for 2 years. The lesion was slightly hypopigmented in its center. Palpation at the periphery revealed a raised annular border.
The clinical examination was in favor of a porokeratosis (Mibelli)

This diagnosis of porokeratosis was easily confirmed with dermoscopy.


The dermoscopic aspect of porokeratosis is a "white track" structure with a brown pigmentation visible in the inside of the track.
This white tract structure corresponds to the cornoid lamella.
In the central part of the lesion, dermoscopy may feature a white area, red dots, globules and lines corresponding to vessels.

Reference: P.Zaballo, S. Puig, J. Malvehy. Dermoscopy of disseminated superficial actinic porokeratosis. Arch Dermatol 2004; 140: 1410

Basal cell carcinoma

A 72-year-old woman consulted for this pigmented lesion on the left side of her nose.

Dermoscopy revealed a non melanocytic tumor with:

• large blue ovoïd nest
• arborizing vessels (in the blue ovoïd nest)
• blue gray globules
• leaf-like areas

in favor of a basal cell carcinoma.

leaf-like structures

Other cases of basal cell carcinomas: 

1 2 3 4 5 6 7 8 9  10 11 12 13 14 15 16 17 18 19 20 21

Labial lentigo

A 15-year-old girl consulted for this acquired pigmented lesion on her lower lip.
This lesion was solitary.

Dermoscopy revealed a pigmentation with a parallel pattern of light-brown to dark-brown streaks which were linear or curvilinear.

This dermoscopic presentation was quite typical of lentigos of the mucous membranes.

We must note that melanoma-specific criteria (atypical pigment network, irregular dots and globules, blue-white veil etc...) are not found in benign lentigos of the oral and genital mucous membranes.

In our case, a biopsy was performed and confirmed the diagnosis of benign labial lentigo.

Arborizing tree vessels

A 79-year-old woman consulted for this lesion near her right ear. This lesion was soft and non ulcerated. The patient did not remember how long it was evolving.

Dermoscopy revealed a homogeneous pattern with many arborizing vessels.

The lesion was excised and pathology was in favor of a benign melanocytic nevus


Arborizing vessels are mainly found in basal cell carcinomas and also rarely in the following lesions:

• melanocytic nevus
• melanoma
• seborrheic keratosis
  

Superficial spreading melanoma

A 66-year-old man consulted for a pigmented lesion on his left scapular area.

Dermoscopy revealed a multi-component pattern, asymmetry, and multiple colours (tan, dark brown, black, blue gray, white).
Other signs were an atypical reticular pattern (irregular holes and thick lines) with a sharp demarcation, a blue-white veil and atypical vessels (irregular linear vessels), a central ulceration (crust). Dots were irregularly distributed.

All these dermoscopic signs were in favor of a superficial spreading melanoma.

Lattice-like pattern

A 17-year-old girl consulted for an acral melanocytic lesion on her left toe.



Dermoscopy revealed a lattice-like pattern in favor of a benign acral melanocytic nevus.

Lattice-like pattern is a subtype of parallel furrow pattern.
It is more often localized on arch areas at the difference of fibrillar pattern which is observed more frequently on pressure areas.

On this figure above, the lattice-like pattern corresponds to the longitudinal and transversal thicker lines and the white circles symbolize eccrine pores.

Other cases of acral nevi:

1  2  3  4  5  6  7  8  9  10  11  

Basal cell carcinoma

A 72-year-old woman consulted for this red left cervical tumor.


Dermoscopy revealed an unspecific pattern and many arborizing blood vessels in favor of a basal cell carcinoma.

Arborizing vessels are the most typical local criteria in basal cell carcinoma.


They are rarely observed in other tumors:

• melanocytic nevus
• melanoma
• seborrheic keratosis
  

Other cases of basal cell carcinomas: 

1 2 3 4 5 6 7 8 9  10 11 12 13 14 15 16 17 18 19 20 21

Glomerular vessels

A 65-year-old woman consulted for this red lesion on her right leg for 8 months. (clinical picture above)

Fig 1: polarized-light contact dermoscopy with a slight pressure
of the dermoscope.

Dermoscopy with a polarized-light contact dermoscope revealed an unspecific pattern and typical glomerular vessels in a symmetric distribution, in favor of a Bowen disease.

Fig 2: polarized-light contact dermoscopy with
a heavier pressure of the dermoscope which emptied
the blood vessels.

Polarized-light dermoscopy offers a better visualization than contact-light dermoscopy for blood vessels whatever the type of vessels, at the condition not to heavily press on the lesion.

Glomerular vessels are the specific local criteria for diagnosing Bowen disease.

Other non specific criteria for Bowen disease are:

• unspecific global pattern
• scales *
  
• ulceration*
  

* not present in our case

Difference between polarized dermoscopy and immersion contact dermoscopy for diagnosis of seborrheic keratosis

Fig 1: clinical view of a seborrheic keratosis

Fig 2: Dermoscopic image taken with polarized dermoscopy

Fig 3: Dermoscopic image of the same seborrheic keratosis taken
with non polarized dermoscopy (immersion contact dermoscopy)

In our case milia-like cysts were better observed with immersion contact dermoscopy.

In an article published in the Archives of Dermatology in 2007 (1) , the authors showed that milia-like cysts and comedo-like openings were better visualized with non polarized dermoscopy (NPD), suggesting that NPD was more helpful for identification of seborrheic keratosis.

1: Benvenuto-Andrade C, Dusza SW, Agero AL, Scope A, Rajadhyaksha M, Halpern AC, Marghoob AA. Arch Dermatol. 2007 Mar; 143(3):329-38. Differences between polarized light dermoscopy and immersion contact dermoscopy for the evaluation of skin lesions.

Keratoacanthoma

This rapidly engrowing lesion for 2 months was clinically in favor of a keratoacanthoma.


In our case dermoscopy revealed:

• an unspecific pattern
• a central ulceration with blood crusts
• a corona of elongated hairpin blood vessels on a white background corresponding to a white keratotic halo
  

Other dermoscopic features of keratoacanthomas are:

• multicomponent pattern
• polymorphous vessels
• central keratotic plug
  

Elongated hairpin blood vessels on a white keratotic halo are non specific of keratoacanthomas and can be observed in invasive squamous cell carcinomas.

Keratoacanthomas is considered as "benign" variant of squamous cell carcinoma. The first line therapy consists in an excision although other alternatives are possible (imiquimod, PDT, etc...)

Other cases: 1

Comma vessels

This is a case of dermal nevus located on the back of a woman.

Comma vessels are well observed on this picture taken with a polarized light dermoscope. Milia-like cysts are present but they are less marked than on pictures taken with dermoscope using immersion principle.

Comma vessels are frequently observed in dermal nevi but can be observed too in atypical nevi.

Solar lentigos

Case 1: clinical image

The clinical aspect of a solar lentigo* is a light brown macule.
(* other denominations: lentigo actinica, senile lentigo)

Case 1: dermoscopic image

2 types of patterns can be observed:

• reticular pattern with regular meshes and thin lines
• homogeneous pattern

In all cases, the pattern has a sharp demarcation and a light brown to tan colour.

Case 2: dermoscopic image

In the 2nd case, the moth eaten borders are one of the typical aspects of solar lentigos.

Another dermoscopic feature sometimes observed is fingerprint-like structures.

Other cases: 1

Halo nevus

A 16-year-old boy underwent a yearly mole check-up. One year later, one of his nevi presented a peripheral depigmentation in favor of halo nevus.



The difference between the two dermoscopic images at a one year interval was very marked:

• depigmentation of the surrounding skin
• enlightening of the global pattern and rarefaction of the globules
  

In this case occuring in a teen, there were no atypical dermoscopic features in favor of a melanoma and another appointment was scheduled one year later.


Halo nevus is a benign lesion and no treatment is required. It is a frequent phenomena during childhood. Despite benign features, the presence of a new halo lesion in an adult has to be examined with a high index of suspcion of melanoma. If a halo nevus is showing atypical dermoscopic features, an excision has to be scheduled.

Melanoma

Asymmetric lesion with pink homogeneous area

A 68-year old man consulted for an atypical pigmented lesion on his left lumbar area.

Dermoscopy revealed a melanocytic lesion characterized by:

• asymmetry
• an atypical pigment network
• a pink homogeneous area
• a white area of regression
• linear-irregular vessels
• polymorphous vessels

Polymorphous and linear-irregular vessels

Atypical pigment network (circle)

White area of regression (circle)

This lesion was highly suspicious of melanoma and excised.

Pathology revealed a superficial spreading melanoma (SSM) in situ developed on a melanocytic nevus developed on a melanocytic nevus

Basal cell carcinoma

A 59-year-old man consulted for this tumor on his nose.

Dermoscopy was typically in favor of a basal cell carcinoma:

• arborizing blood vessels
• blue ovoid nest
• blue gray globules
• ulceration with congealed blood
  

Other cases of basal cell carcinomas: 

1 2 3 4 5 6 7 8 9  10 11 12 13 14 15 16 17 18 19 20 21

Basal cell carcinoma

A 89-year-old woman consulted for a pigmented lesion on her forehead. A basal cell carcinoma was the main clinical diagnosis.

On this picture, with a slight pressure of the dermoscope (polarized light dermoscopy), arborizing blood vessels are well seen.
Blue gray dots and globules are the other dermoscopic signs in favor of this basal cell carcinoma.

If the pressure of the dermoscope is too important, the blood vessels are not visible.

Vessels and red areas are better visualized with polarized light dermoscopy than with immersion contact dermoscopy (1)

References:
1 - Marghoob et al. Differences between polarized light dermoscopy and immersion contact dermoscopy for the evaluation of skin lesions. Arch Dermatol 2007 Mar;143(3):329-38