Reflectance confocal microscopy role in mycosis fungoides follow-up

Background: Reflectance confocal microscopy (RCM) is a useful tool for many skin cancers, allowing non-invasive evaluation over time and identifying areas of active disease. Its role to follow-up mycosis fungoides (MF) patients has not yet been evaluated. Objective: To assess the level of agreement between RCM and histopathology and to develop a RCM checklist that could help monitoring MF patients. Method: Prospective study in a cutaneous lymphoma clinic of a tertiary hospital in Australia. RCM and biopsies were performed on the same area at baseline, before commencing or changing treatment, and at 6 months after starting treatment. Normal skin sites were also analysed and acted as controls. RCM features and histopathological findings were blindly evaluated by the confocalist and pathologist. Correlation between RCM and histology was measured by overall per cent of agreement (OPA), kappa and ROC curves. Additionally, RCM images before and after treatment were assessed blinded from clinical information and correlated to clinical assessment. Results: Thirty-eight MF lesions were included. Nineteen of these 38 were re-assessed by RCM 6 months later. Fifty biopsies were performed (38 at baseline and 12 after 6 months). The combination of four RCM features corresponding to Pautrier's microabscess, epidermal and junctional lymphocytes and interface dermatitis formed the RCM checklist for MF that predicted the severity of disease with AUC of 0.95 (P =.003). Conclusion: Reflectance confocal microscopy can assess activity within a lesion and over time and assist in the clinical management of patients with MF.