Melanoma in situ

A 65-year-old woman presented a changing of color and size of one of her nevi. This nevus was localized on her back.

Dermoscopy revealed a central part with aggregated globules and an atypical and asymmetric reticular pattern.

This lesion was excised and pathology revealed a melanoma in situ in association with a dermal nevus.

Asymmetry is one of the most important parameters of melanomas in situ.

Symmetric blotch

Fig 1 Blotch

A blotch (fig 1)  is a dark-brown or black structure-less area where other dermoscopic features cannot be seen. Symmetric blotches are in favour of benign lesions. Assymetrically distributed blotches are in favour of melanomas.

In our case, the blotch was symmetrically disposed and a peripheral reticular network was visible. This kind of blotch is also called black lamella.

This lesion was corresponding to a benign melanocytic nevus.

It has to be distinguished from the blue structure-less pattern or blue homogeneous pattern of a blue nevus (fig 2).

Fig 2 Blue homogeneous pattern

Clear cell hidradenoma

Fig 1: clinical picture

A 52-year-old man consulted for a scapular nodule. Clinical examination revealed a flesh-coloured nodule (Fig 1)

Fig 2 dotted vessels

Polarizing dermoscopy with a slight pressure revealed dotted vessels (Fig 2)

Fig 3 whitish areas

Fig 4 whitish areas

Dermoscopy with a louder pressure revealed whitish areas (Fig 3 and 4).

This lesion was excised and pathology revealed a clear cell hidradenoma.

Clear cell hidradenomas are usually benign intradermal tumors and represent 95% of all hidradenomas. These tumors have a slow growth and sometimes can be ulcerated. Theay have to be surgically excised because of a high risk of recurrence and a potential of malignant evolution.

Y. Yoshida and al. reported dermoscopic features of a clear cell hidradenoma (Y. Yoshida and al. Dermatology 2008;217: 250-251).

They found in their case whitish areas, reddish purple areas, and some linear or hairpin vessels on the surface of the tumour. Reddish purple areas were corresponding to cystic spaces with hemorrhage.

Fat fingers

Typical presentation of a seborrheic keratosis with network like structures and fat fingers.

In this case there are no other signs of seborrheic keratosis (milia-like cysts, comedo-like openings, fingerprint-like structures, hairpin blood vessels)

Blue-gray globules

A 67-year-old woman consulted for this lesion on her back. Dermoscopy revealed blue-gray globules (rectangle) and some arborizing vessels (arrows) confirming easily the diagnosis of basal cell carcinoma.

Blue-gray globules are a pathognomonic sign  in pigmented basal cell carcinoma. 

They are often associate with other basal cell carcinoma specific criteria, as leaf-like structures,

spoke-wheel areas and  large blue-gray ovoid nests.

Arborizing tree vessels

A 54-year-old woman consulted for this small pink lesion on her scalp (parietal area)

Dermoscopy revealed many arborizing vessels in favour of a basal cell carcinoma.

The lesion was excised and pathology confirmed the clinical and dermoscopic diagnoses.

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.

Red lacunes on the ridges

A 28-year old-woman consulted for this dark red acral lesion present since early childhood.

Dermoscopy revealed many red saccules (or lacunes) located on the ridges with a parallel pattern.

This dermoscopic feature was in favor of an hemangioma or an hemolymphangioma

Plantar nevus

A 25-year-old woman consulted for a pigmented lesion on her right foot.

Dermoscopy revealed a parallel furrow pattern and a whitish structureless area.

On the middle of this structureless area a keratotic lesion was noticed in favor of a callus.

An excision was performed and pathology revealed a benign melanocytic nevus.

The structureless area was caused by the chronic friction of this nevus against shoes.

Whitish area

A 17-year-old girl presented a pigmented lesion with a lateral  depigmentation.

Dermoscopy  revealed a globular pattern associated with a whitish structureless area. On this whitish area some vessels were observed. There were no signs of peppering.

This lesion was excised and pathology revealed a benign dermal melanocytic nevus with a fibrous involution.

Whitish structureless area can be observed in:

• fibrous involution
• after traumatism
• in case of regression (with peppering)

Lattice-like pattern

A 14-year-old girl consulted for this small plantar nevus.

Dermoscopy revealed a typical lattice-like pattern which is a subtype of parallel furrow pattern in favour of a benign acral plantar nevus.

Other cases of acral nevi:

1  2  3  4  5  6  7  8  9  10  11  

Acral melanocytic nevus

A 48-year-old woman consulted for this pigmented lesion on her 5th right finger present since early childhood. 

Dermoscopy revealed a parallel furrow pattern and in some areas a lattice-like pattern.

The dermoscopic features were in favor of a benign acral nevus.

A regular yearly follow-up was planned.

In parallel furrow pattern, the pigmentation follows the sulci at the difference of parallel ridge pattern where the pigmentation follows the cristae.

In Acral melanocytic nevi, 3 types of patterns can be observed:

• parallel furrow pattern
• lattice-like pattern
• fibrillar pattern

Parallel ridge pattern are typical of acral melanomas but can be observed in other cases:

• milk-line nevus
• subcorneal hemorrhages (talon noir)

Other cases of acral nevi:

1  2  3  4  5  6  7  8  9  10  11  

Leaf-like structures

A 92-year-old woman presented a red tumor on her neck.

Dermoscopy revealed many brown structures with a leaf-like configuration located at the periphery of the lesion. This was typical of leaf-like structures, also called maple leaf-like areas in the first publications.

Leaf-like structures are quite exclusively found in basal cell carcinomas but have also been reported in featureless melanomas.

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

Hairpin-like vessels and seborrheic keratoses

These 2 cases of seborrheic keratoses are dysplaying hairpin vessels:

Case 1: clinical view

Case 1: dermoscopic view: numerous hairpin blood vessels 

Case 2: dermoscopic view: rare hairpin vessels

Hairpin vessels can be found in:

• seborrheic keratoses (fine, often surrounded by a hypopigmented halo)
• Melanoma (irregular)
• Spitz nevi
• keratoacanthomas

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