Abstract

Pigmented actinic keratosis (PAK) and lentigo maligna (LM) may be challenging to distinguish on facial skin. Specific dermatoscopic features may differentiate them, but when the lesions are small, dermatoscopic features might not be as helpful. Typically, PAK presents with prominent follicular openings on an erythematous background and perifollicular pigmentation on dermatoscopy, whereas LM shows a rhomboidal pattern, annular granular structures, and grayish discoloration. In the early stages of LM, dermatoscopic features are subtle thus dermatoscopic criteria might not be sufficient for diagnosis. RCM is a noninvasive imaging technique which allows visualization of the epidermis horizontally to a depth of 200 microns, enabling clinicians to recognize early histologic features of LM. RCM is a useful tool to distinguish LM from other facial lesions by showing folliculotropism of atypical cells, nonedged papillae, and round pagetoid cells >20 microns. In contrast, PAK typically shows epidermal changes such as hyper-parakeratosis, atypical keratinocyte proliferation at lower parts of the epidermis, and lack of melanoma specific features including nesting, atypical melanocytic cells at the dermo-epidermal junction and lack of folliculotropism on RCM. Herein, we present examples of PAK and LM and compare and contrast their RCM features. Comparison between these two lesions can increase diagnostic accuracy for pigmented facial macules and may enable physicians to diagnose LM in earliest stages.

Financial Disclosure:
The poster abstract presenter listed below disclosed the following information about their financial interests. The ASDP Ethics Committee has reviewed these disclosures and determined that no conflicts of interest exist between financial relationships and educational content being presented.

Speaker	Company	Affiliation/Relationship
Babar Rao, MD	Caliber Imaging & Diagnostics	Consultant