ABSTRACT
Targetoid hemosiderotic nevus (THN) is a rare variant of melanocytic nevus, characterized by a sudden development of a targetoid ecchymotic halo around a pre-existing nevus. THN clinically raises concern for malignant transformation due to its abrupt change in color and size. THN should be distinguished from other diseases showing a peripheral halo, including targetoid hemosiderotic hemangioma, halo nevus, and Meyerson nevus. Dermoscopy can help clinicians to differentiate THN from these diseases. The typical dermoscopic features of THN are known to be divided into two distinctive areas: the central melanocytic area and the peripheral ecchymotic area. In our case, dermoscopy revealed a novel bull’s eye pattern composed of a central area with characteristic features of benign melanocytic nevus, an intermediated white circular ring, and a peripheral milky red area. When a sudden change occurs in a pre-existing nodule showing targetoid features, dermoscopy should be considered before conducting a biopsy or surgical intervention.
ABSTRACT
Background@#Lichenoid drug eruption (LDE) is a relatively rare form of cutaneous drug eruption and that resembles lichen planus on a clinical and histological basis. Although there are some studies on histopathological findings of LDE, studies on clinical findings of LDE are limited. @*Objective@#To investigate the clinical and histopathologic findings and prognosis of LDE. @*Methods@#We retrospectively investigated the clinicopathologic findings of LDE patients who visited Kosin University Gospel Hospital between 1990 and 2020. @*Results@#This study included 44 LDE patients (male:female=1.4:1). The most common causative drug was anti-tuberculous drugs (52.3%), followed by 5-fluorouracil (11.4%), and captopril (9.1%). There were pruritic erythematous scaly or lichenoid patches and plaques in all cases. The most frequently involved sites were trunk and extremities. Notably, 15 cases (34.1%) involving the scalp and 3 cases (6.8%) involving the oral mucosa. Treatment modalities included oral, topical corticosteroid, and oral antihistamines. Among 44 cases, 28 patients discontinued the causative agent, and 16 patients continued to use it after diagnosis of LDE. The mean duration of treatment for patients who discontinued or did not discontinue the causative drugs was 4, 10 weeks, respectively. The most commonly observed histopathologic findings were superficial and deep perivascular infiltration of inflammatory cells (100.0%) and eosinophil infiltration (93.2%). @*Conclusion@#LDE can be differentiated from idiopathic lichen planus by clinicopathologic findings. LDE appears to be a mild form of drug eruption in which symptoms can be controlled with conservative treatment, even without the cessation of causative drugs for the treatment of the underlying disease.