Clinical and dermatoscopic characteristics of lichen planus-like keratosis in a West-Asian population.

Background/objective: The clinical and dermatoscopic features of lichen planus-like keratosis have been described but the characteristics of this entity in a West-Asian population are not known.

Methods: We retrospectively analysed 82 histopathologically verified cases of lichen planus-like keratosis from 81 patients from Iran and Turkey.

Results: The majority of lichen planus-like keratoses were macules (61% n = 50), clinically pigmented (67.1% n = 55) and dermatoscopically multi-coloured (91.5% n = 75). The majority (63.4%) had a single dermatoscopic pattern, most frequently: structureless (35.4%), dots (14.6%) and angulated lines (8.5%). Of the lesions with more than one pattern (n = 30), the majority (n = 21) had asymmetry of pattern, the most common combinations being structureless plus dots (n = 8) and structureless plus angulated lines (n = 5). The most common structure was pigmented dots, most frequently grey and present in 70.7% of cases. Vessels were seen in 30.5% of lesions, being significantly more prevalent in non-pigmented, than pigmented, lichen planus-like keratoses (83.3% vs. 21.4% P < 0.001). When we compared lichen planus-like keratosis in the current study to that entity in a large North American study, the statistically significant differences in a West-Asian population included a greater frequency of pigmented variants, a lower incidence in females and a lower prevalence on the torso, in favour of the face.

Conclusions: Lichen planus-like keratosis in a West-Asian population has clinical and dermatoscopic similarities to that entity in another studied population. The significant differences in gender association and anatomical site may be secondary to cultural factors.