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)

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.