Dermoscopy for Discriminating Between Lichenoid Sarcoidosis and Lichen Planus

Abstract

T HE LESIONS SHOWN WERE LOCATED ON the forearm of a 47-year-old man (Figure 1A), the forearm of a 51-yearold man (Figure 1B), and the trunk of a 55-year-old woman (Figure 1C), all of them presenting with a lichenoid rash. Dermoscopy revealed 2 differential patterns in these lesions: (1) reticular, white Wickham striae (WS) (Figure 2A) in the papules shown in Figure 1A and (2) round to oval, yellowbrown, homogeneous patches (YPs) (Figure 2B and C) and absence of WS in the lesions shown in Figure 1B and C. A histopathologic diagnosis of lichen planus (LP) was made in 1 patient (Figure 1A, inset), and lichenoid sarcoidosis was diagnosed in the other 2 patients (Figure 1B and C, insets). Lichenoid sarcoidosis represents 1% to 2% of cutaneous sarcoidosis cases and mimics LP. The examples illustrated herein show that dermoscopy may be useful for discriminating between the lesions of LP and those of lichenoid sarcoidosis. The absence of WS and the presence of YPs should prompt clinicians to perform a biopsy to rule out a granulomatous skin disease in clinically lichenoid lesions. Dermoscopy and diascopy of sarcoidosis lesions reveal individual yellow nodules (“grains of sand”) or a yellow-brown discoloration (“applejelly” sign). Yellow-brown homogeneous patches are not specific for sarcoidosis, but they are indicative of a granulomatous skin disease (sarcoidosis, lupus vulgaris, leishmaniasis). Conversely, dermoscopy of active LP lesions reveals the characteristic WS but not the YPs.