Copyright 2016 American Medical Association. All rights reserved. A Digital Dermoscopy Follow-up Illustration and a Histopathologic Correlation for Angulated Lines in Extrafacial Lentigo Maligna Alexia Vanden Daelen, MD; Ingrid Ferreira, MD; Liliane Marot, MD; Isabelle Tromme, PhD L entigo maligna (LM) constitutes the noninvasive phase of lentigo maligna melanoma. Although LM is still in situ, it should be diagnosed and treated given the risk of pro- gression to invasive melanoma. Lentigo maligna typically oc- curs on chronically sun-exposed skin, such as that of the head and neck, and less frequently on the extremities of elderly in- dividuals. Extrafacial LM (EFLM) was first described by Sir John Hutchinson in 1890 1 and is therefore called Hutchinson mela- noma. These EFLMs account for 17.5% of all cases of LM ac- cording to a 10-year analysis of the Scottish Melanoma Group database. 2 The dermoscopic features of LMs of the head and neck are well known and are related to the facial skin anatomy charac- terized by the absence of rete ridges, multiple pilosebaceous units, and photoinduced elastosis. The dermoscopic features of LM were defined in 2000 by Schiffner et al. 3 The progres- sive invasion by malignant cells can be observed in dermos- copy by the appearance of asymmetrical pigmented follicular openings, a perifollicular annular-granular pattern, pig- mented rhomboidal structures, and obliterated hair follicles. Slutsky and Marghoob 4 described a zigzag pattern of angu- lated, linear pigmented lines on facial LMs. Pralong et al 5 described 4 additional original criteria: increased vascular network, targetlike images, red rhomboidal structures, and darkening at dermoscopic examination. Less is known regarding the dermoscopic features of EFLM. In 2013, Lau et al 6 performed a study of 3 cases featuring the dermoscopy of extrafacial LMs. They proposed that they could share a combination of dermoscopic features of LM (pigmented rhomboidal structures and asymmetrical perifol- licular pigmentation) and superficial spreading melanoma in situ (irregular dots and streaks and an irregular pigmented network). Two new EFLM criteria have been described by Keir 7,8 :a lentigo-like pigment pattern lacking a lentigo-like border and complete or incomplete large polygonal shapes defined by darker gray or brown straight lines or formed by the straight edge of a junction between lighter and darker areas of the lesion. Jaimes et al 9 recently proposed the new term angulated lines to integrate all of the different linear dermoscopic pat- terns previously described, such as the rhomboidal struc- tures by Schiffner et al 3 and the zigzag pattern by Slutsky and Marghoob, 4 both features described on facial LMs, and the larges polygones described by Keir 7 on EFLM. However, even though they may look geometrically similar superficially, it is not proven whether they share the same biological or patho- logic process. 9 We report 3 cases by digital follow-up in which straight an- gulated lines were seen on extrafacial pigmented lesions and IMPORTANCE The diagnosis of extrafacial lentigo maligna can be a challenge because the dermoscopic features are not well described. These features can share some of the criteria of superficial spreading melanoma and some of facial lentigo maligna; however, these features are often absent. A new dermoscopic pattern has recently been described as forming angulated lines. OBSERVATIONS We report 4 cases of extrafacial lentiginous lesions in 3 patients in whom straight angulated lines have been observed as the only key for diagnosis. This is the first time, to our knowledge, that these lines were seen in the follow-up by digital dermoscopy during a lapse time of a few months. This morphologic change led to the excision of the lesion. The pathologic diagnosis of lentigo maligna was established in each case. Moreover, a histologic correlation of these straight angulated lines is documented. CONCLUSIONS AND RELEVANCE Angulated lines could be considered as a new warning sign during the follow-up of extrafacial lentigo. More studies are required to establish the sensitivity and specificity of this newly described dermoscopic feature. JAMA Dermatol. 2016;152(2):200-203. doi:10.1001/jamadermatol.2015.4132 Published online December 9, 2015. Author Affiliations: Department of Dermatology, Cliniques Universitaires Saint-Luc, Brussels, Belgium (Vanden Daelen, Marot, Tromme); Department of Pathology, Cliniques Universitaires Saint-Luc, Brussels, Belgium (Ferreira, Marot). Corresponding Author: Alexia Vanden Daelen, MD, Department of Dermatology, Cliniques Universitaires Saint-Luc, Avenue Hippocrate 10, 1200 Brussels, Belgium (alexia .vandendeaelen@uclouvain.be). Research Case Report/Case Series 200 JAMA Dermatology February 2016 Volume 152, Number 2 (Reprinted) jamadermatology.com Copyright 2016 American Medical Association. All rights reserved. Downloaded From: https://jamanetwork.com/ on 05/22/2020