Dendritic cells in reflectance confocal microscopy are a clue for early melanoma diagnosis in extrafacial flat pigmented melanocytic lesions.

Differential diagnosis of extrafacial flat pigmented lesions with dermoscopic reticular and/or homogeneous pattern is challenging. Dendritic cells upon reflectance confocal microscopy (RCM) still represent a pitfall. This study aims to determine the role of dendritic cells upon RCM in the epidermis and dermo-epidermal junction (DEJ), together with common RCM features for melanoma and nevi, in dermoscopically equivocal extrafacial flat pigmented lesions. A retrospective evaluation of RCM images of melanocytic extrafacial flat pigmented lesions with reticular and/or homogeneous dermoscopic pattern and with histopathological diagnosis, was performed. A multivariate model of RCM features was used to obtain a score of independent risk factors. A total of 698 lesions were included. Increasing patient age, epidermal dendritic cells, many dendritic cells in the DEJ (>30%) and many (>5/mm2 ) round atypical cells were independent risk factors for melanoma. Edged papillae and melanophages were indicative of nevus. A score based on these features was developed to assist in melanoma differential diagnosis. The RCM observation of abundant (>30%) dendritic cells in the DEJ is highly suggestive of malignity. This independent risk factor should also be considered for improved differential diagnosis of extrafacial melanoma.

Treatment monitoring of 5-fluorouracil 0.5%/salicylic acid 10% lesion-directed therapy for actinic keratosis using dermoscopy and in-vivo reflectance confocal microscopy.

Recently, 5-fluorouracil 0.5%/salicylic acid 10% (5-FU/SA) topical solution has been included in the National Italian portfolio for lesion-directed treatment of grade I/II actinic keratosis (AKs) located on the face or scalp. To describe the utility of dermoscopy and RCM in treatment response monitoring of a series of AKs treated with 5-FU/SA as lesion-directed therapy. Consecutive patients were prospectively treated for a maximum of 12 weeks with 5-FU/SA for AKs located on the face or scalp. Clinical, dermoscopic, and confocal images of one index AK were acquired at each visit and pre-specified criteria were evaluated. Clinical, dermoscopic, and confocal responses were evaluated at last follow-up visit. Fourteen patients were enrolled, of which five were treated for 12 weeks, seven for 8, and two for 4 weeks. At a median follow up of 30 weeks, 64.3% (9/14) index AKs achieved complete clinical, 50% (7/14) complete dermoscopic and 42.9% (6/14) complete confocal clearance. Local skin reaction was mild and significantly decreased during therapy administration. Although the small number of cases, our study underlines the utility of both dermoscopy and in-vivo RCM in 5-FU/SA treatment response monitoring for AKs located on the face or scalp.