Objective To compare identification of the border of lentigo maligna (LM) with digital epiluminescence microscopy (DELM) with clinical and Wood light assessment.
Design The borders of lesions identified clinically with the Wood light, with DELM, and after excision by Mohs micrographic surgery were traced onto plastic sheets. The borders defined on the tracings were compared for congruence and mean surface area.
Setting Cardinal Bernardin Cancer Center for Skin Cancer, Loyola University Health System, Maywood, Ill.
Patients Twenty-six consecutive patients with LM of the head and neck.
Main Outcome Measures Results of the comparison of the outlines of the borders and the mean surface area identified by the 4 methods.
Results The border determined by clinical examination was smaller than that determined with the Wood lamp or by DELM. Most lesions underwent an additional excision 5 mm beyond the DELM-defined border. The DELM pattern of LM with asymmetric follicular openings and dark brown rhomboidal structures changed at the periphery and became a pigmented thin mesh that was associated with the histopathological features of melanoma in situ. More homogeneous pigmented areas extending from the LM were associated with the pathologic features of melanocytic hyperplasia.
Conclusions Visualization of LM by DELM (dermoscopy) helps to guide resection. Because LM arises in sun-damaged skin with melanocytic hyperplasia, determining the tumor-free margin requires the judgment of an experienced physician.
