Benign Keratosis: A Useful Term?

Abstract

Introduction: Seborrheic keratosis (SK), lichen planus-like keratosis (LPLK), and solar lentigo (SL) are common benign skin lesions. These lesions are frequently seen adjacent to each other or can arise from one another. They can sometimes be difficult to differentiate despite having distinct histopathological features.

Objectives: We evaluated dermoscopic images of 80 skin lesions to confirm the term 'benign keratosis' is useful for an undifferentiated SK/LPLK/SL where there are overlapping clinical and dermoscopic characteristics.

Methods: Clinical and dermoscopic images were sourced from a teledermoscopy service database of 13,000 lesions in 7,000 patients. The database was queried for SK, SL or LPLK in sun-exposed sites. Each lesion was evaluated based on specific dermoscopic criteria and the results analyzed.

Results: Lesions were identified with mixed clinical and dermoscopic criteria of SK and SL, and in some, dermoscopic criteria for LPLK were also present.

Conclusions: This study highlights the relationship between these lesions. We confirm the term 'benign keratosis' is useful for mixed lesions or for those that are difficult to classify.

Figure 1

Mixed Lesion displaying appearance of SK arising from SL. Lesion ID 15040477. Dermoscopy features —sharply demarcated border, dots or clods white clustered or disseminated, clods brown yellow or orange (rarely black), Lines curved and thick (cerebriform), lines brown curved parallel thin, faint reticulation (criss-cross network), scalloped border, fine lines parallels.

Figure 2

Seborrhoeic Keratosis classical lesion. Lesion ID 35110201. Dermoscopy features — sharply demarcated border, dots or clods white clustered or disseminated, clods brown-yellow or orange (rarely black), lines curved and thick (cerebriform), lines brown curved parallel thin.

Figure 3

Solar Lentigo classical lesion. Lesion ID 44740194. Dermoscopy features — sharply demarcated border, homogenous brown pigmentation, structureless (approx. 10%), faint reticulation (criss-cross network), scalloped border, fine lines parallel.

Figure 4

Lichen Planus-like Keratosis classical lesion. Lesion ID 46600410. Dermoscopy features — structureless (approx. 10%), faint reticulation (criss-cross network), scalloped border, grey dots, diffuse grey dotted pattern.