Dermoscopy

Question 1

Answer 1

Asymmetrical perifollicular pigmentation in lentigo maligna

Lentigo maligna in areas with high follicular density may show increased pigmentation around these follicles, giving an
appearance of pigmented circles.

Stolz proposed a dermoscopic model of progression of lentigo maligna. As the lentiginous proliferation develops, ­ dermoscopic features progress from annular granular pigmentation to asymmetry of perifollicular pigmentation, rhomboidal structures and, finally, follicular destruction as the tumour becomes invasive.

Three dermoscopic clues to look for are: irregular brown/
grey granular pigmentation, irregular perifollicular pigmentation, ill-defined peripheral margins.

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Question 8

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A tan macule on the arm of a 60-year-old woman: dermoscopy shows a well-demarcated moth-eaten peripheral border, homogeneous pigmentation with skin surface markings and regular follicular apertures in this solar lentigo.

Question 9

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Multiple tan macules across the upper back of a 60-year-old man: dermoscopy shows uniform reticular pigmentation and double lines in this solar lentigo

Question 10

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Multiple hyperpigmented macules across the upper back of a 70-year-old man with high UV exposure: dermoscopy shows
uniform reticular pigmentation in this hyperpigmented ‘ink spot’ lentigo.

Question 11

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An angulated tan macule on the forearm of a 60-year-old man: dermoscopy shows a well-demarcated peripheral border, follicular openings and a zone with a ceribriform pattern in this solar lentigo with evolving seborrhoeic keratosis.

Question 12

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A brown warty plaque on the zygoma of a 70-year-old female: dermoscopy shows a uniform cerebriform pattern and multiple ‘fat fingers’ in this seborrhoeic keratosis.

Question 13

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Parallel furrow pattern found just inside of the weight-bearing skin.

The parallel furrow pattern of pigmentation is the principal morphology seen in acral naevi. The lines of pigment are thin and originate in the furrow of the acral dermatoglyphics. The ridges of the dermatoglyphics are highlighted by the presence of white dots correlating to the eccrine gland openings. Dermatoglyphics is a word deriving from the Ancient Greek language for skin carving. This feature, which is shared with primates, enhances grip.

Question 14

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Lattice pattern found on the instep

Lattice pigmentation is a variant of parallel pigmentation whereby the pigment links adjacent parallel furrow lines. On the soles, it typically signifies naevi located on the instep.

Question 15

Answer 15

Fibrillar pattern found on weight-bearing skin.

Fibrillar pigmentation is a variant of parallel pigmentation whereby the pigment produced migrates from the point of origin across the dermatoglyphics. The pigmented lines are uniform and thin and run perpendicular to the dermatoglyphics. This pattern is created by pressure effects and typically occurs on weight-bearing areas on the sole. Beware of the atypical fibrillar pattern which is a potential clue to melanoma.

Question 16

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A 3 mm junctional naevus on the palm of a 20-year-old woman: dermoscopy shows the parallel furrow pattern with thin strands outlining the grooves in the dermatoglyphics.

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A 5 mm pigmented macule on the lateral sole of a 40-year-old woman: dermoscopy shows a chaotic and atypical reticular pattern with both grey hues and black globules with histopathology showing melanoma in situ (MIS).

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Question 21

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