Role of dermoscopy

Abstract

Lentigo maligna (LM)/lentigo maligna melanoma (LMM) typically presents as an isolated pigmented macule or patch on chronically sun damaged skin. At early stages in its clinical presentation the appearance of LM/LMM overlaps with solar lentigo, macular seborrheic keratosis, pigmented actinic keratosis, and lichen planus-like keratosis. Consequently, LMM diagnosis is often delayed or unnecessary biopsies of the aforementioned benign entities are frequently performed. Use of dermoscopy, however, improves diagnostic accuracy for LMM and limits biopsies of its benign simulators. Common dermoscopic features associated with LMM include the presence of asymmetrically pigmented or gray-colored follicular openings and peri-follicular grey dots/granules, which produce the so-called “annular-granular pattern. In addition, LMM can have angulated pigmented lines that join to create zigzag lines or polygonal structures such as rhomboids. In addition to helping with the primary diagnosis of LMM, dermoscopy is used to optimize biopsy site selection, to select treatment margins, and to identify potential recurrence during post-treatment monitoring. Lentigo maligna/lentigo maligna melanoma (LM/LMM) usually presents as an isolated pigmented macule or patch on chronically sun damaged skin. In its early stages its clinical presentation overlaps with solar lentigo, flat seborrheic keratosis (SK), pigmented actinic keratosis (AK), and lichen planus-like keratosis (LPLK), presenting a diagnostic challenge. As a result, LMM is often not recognized and diagnos is delayed [1]. While Wood’s lamp examination can help to accentuate lesion pigmentation for border detection, it cannot reliably help in differentiating LM/LMM from its benign mimickers [1]. Fortunately, ancillary non-invasive tools such as dermoscopy and reflectance confocal microscopy (RCM) can improve our diagnostic accuracy for LM/LMM as well as for solar lentigo, flat SK, pigmented AK, and LPLK. Although RCM is quite useful for the diagnosis of LM/LMM, dermoscopy remains the primary imaging instrument used to help identify lesions with the highest likelihood of being LM/LMM. Besides helping in the identification of LM/LMM, dermoscopy can improve LM/LMM margin delineation and to detect potential recurrence after definitive treatment. Finally, when examining LM/LMM lesions with skip areas or clinically discontinuous foci, dermoscopy can aid in biopsy site identification [1, 2].