2 colors, 1 diagnosis

A 45-year-old woman was referred for this pigmented lesion with 2 colors.

Diagnosis was easy with dermoscopy:

• comedo-like openings 
• milia-like cysts
• fissures and ridges 
• network-like structures
• sharp demarcation

in favor of a seborrheic keratosis

Black lesion is back

A 65-year-old man consulted for a dark pigmented lesion on his back.
Dermoscopy revealed:

• absence of pigment network
• milia-like cysts
• comedo-like openings

in favor of a seborrheic keratosis.

Seborrheic keratosis

A 50-year-old woman consulted for an enlarging and pruritic lesion on her back.

This pigmented lesion was characterized in dermoscopy by:

• absence of pigment network
• sharp demarcation
• presence of milia-like cysts
• comedo-like openings

This dermoscopic presentation was typical of a seborrheic keratosis.

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.

Seborrheic keratosis

A 47-year-old woman consulted for this dark pigmented lesion on her neck.


Dermoscopy featured comedo-like openings (yellow arrows) and crypts (red arrow). There was no pigment network and the lesion was sharp demarcated.
These different criteria were in favor of a seborrheic keratosis.


It is important to remind that no single criterion by itself is diagnostic and an accurate and complete examination of the different dermoscopic features is necessary before diagnosing a seborrheic keratosis.

Milia-like cysts

This patient presented an enlarging pigmented lesion on her back for 2 years.


Dermoscopy: lack of pigmented network, sharp borders, comedo-like openings and many milia-like cysts were in favor of a a seborrheic keratosis.


Many milia-like cysts like stars in the sky are typically found in seborrheic keratoses.

Milia-like cysts and comedo-like openings

A 74-year-old man consulted for a pruritic pigmented lesion on his back.


Dermoscopy was in favor of a seborrheic keratosis: pigmentation with sharp demarcation, milia-like cysts and comedo-like openings.


Milia-like cysts are white or yellow, round bodies, frequently observed in seborrheic keratoses. They can be seen in compound or dermal nevi, melanomas, pigmented basal cell carcinomas but are usually solitary or in a small number.


Comedo-like openings are pigmented and ovale yellowish, brown or black structures. They can also be observed in melanocytic lesions and melanomas.

Unna nevus

Melanocytic nevus on the abdomen of a 35-year-old woman.
Dermoscopy reveals exophytic papillary structures, comedo-like openings, milia-like cysts and comma-like vessels.

Acanthotic seborrheic keratosis

A 76-year-old woman presented a seborrheic keratosis on her back.
It was an acanthotic type.
In dermoscopy, the lesion presented a sharp demarcation, a dark-brown background coloration on the left part of the lesion , numerous milia-like cysts (black circle), comedo-like openings (blue lines), and crypts (red circle)

Unna nevus

A 39-year-old woman consulted for an abdominal pigmented lesion.
Dermoscopy revealed exophytic papillary structures (*), clustered milia-like cysts (black circle), comedo-like openings (blue circle).
The wobble sign was present in favor of a Unna nevus.
The wobble sign is a useful sign when it is difficult to share between a Unna nevus and a seborrheic keratosis: the dermoscope put on the lesion is moved; if the lesion wobbles, it is a Unna nevus at the difference of a seborreic keratosis which does not wobble.

Seborrheic keratosis

A 50-year-old woman presented a pigmented tumor on her left arm.
Dermoscopy revealed many comedo-like openings, crypts, and milia-like cysts inf favor of a seborrheic keratosis.