Lentigo maligna (LM) is in situ melanoma and has a risk of transformation to invasive melanoma (Lentigo Maligna Melanoma (LMM)). Optimal management of LM and LMM is complicated and controversial as the lesions are often large, have subclinical areas (unable to be identified by clinical inspection alone) and additionally its extent is often poorly defined.
Current management of LM and LMM recommends complete excision, and is currently done by slow Mohs with an excision section every 2-3 days until clearance is achieved. Defining the area of lentigo through clinical inspection alone often underestimates the size of the lesion, as nearby “apigmented” skin is often involved. In vivo reflectance confocal microscopy (RCM) has been proven to detect subclinical LM and LMM in non periocular skin. This study reports the application of this technology to the periocular area.

Patients referred for slow mohs excision of lentigo maligna over the last year were included. Photos of the lesion were taken. In vivo confocal microscopy was performed and the abnormal area identified and marked. The patients then underwent slow Mohs excision and the area of excision required pathologically was compared to the confocal area and clinical inspection area.

3 patients were included. In all three, clinically visible lesions had additional subclinical areas identified by in vivo RCM, and corresponded to the area excised to ensure clear margin excision pathologically (photos included on poster).

In vivo RCM can identify areas of periocular lentigo maligna(LM) and Lentigo Maligna Melanoma (LMM), not clinically apparent through inspection alone. This imaging can reduce the number of excision sections required, reduce theatre time, improve surgical reconstruction planning and help patients to understand their postoperative result.