Assessment of reflectance confocal microscopy for monitoring treatment of actinic keratosis and field cancerization with daylight photodynamic therapy.

Actinic keratosis (AK) is the most common pre-malignant cutaneous lesion of the skin, often associated with field cancerization. Daylight photodynamic therapy (DL-PDT) is used as treatment, showing good histological results. Reflectance confocal microscopy (RCM) may be useful as a non-invasive, real-time approach to monitor treatment, however, there is a lack of data on the correlation between RCM and histopathological findings in AK patients treated with DL-PDT. To correlate histological and RCM findings and evaluate the efficacy of DL-PDT in patients with AK and field cancerization treated with DL-PDT. Patients with field cancerization and a minimum of six AK lesions on the face were included in the study. A single session combining methyl aminolevulinate followed by two-hour daylight exposure of the face was performed. RCM and biopsy were performed before and after three months of the intervention to compare efficacy between patients using the Wilcoxon test, and concordance of the findings based on the different methods was analysed using the Kappa test. Twenty-four patients completed the study. An improvement in photodamage and a decrease in the number of AK lesions (45.3% reduction) was observed. Regression in atypia and dysplasia was observed via histopathology and RCM, however, there was poor agreement between the methods. No changes were observed after treatment for inflammation, fibroplasia and acantholysis. Concordance between histological and RCM findings was poor, suggesting that RCM cannot replace the histopathological examination, however, it may be used as an adjuvant test for follow-up of patients. Despite this, DL-PDT proved to be an effective method for treating AK.

Clinical and Histopathologic Assessment of Facial Melasma After Low-Fluence Q-Switched Neodymium-Doped Yttrium Aluminium Garnet Laser.

BACKGROUND: Melasma is a frequent and difficult to treat skin disorder. Results of laser therapy are inconsistent. OBJECTIVE: To determine the safety and efficacy of low-fluence Q-switched neodymium-doped yttrium aluminum garnet (QS Nd:YAG) laser for melasma treatment and assess recurrence rates and histopathologic findings before and after treatment. METHODS: Twenty patients were treated with 10 weekly sessions of low-fluence 1064-nm QS Nd:YAG laser at 1-week intervals. The modified Melasma Area and Severity Index (mMASI) score was evaluated at baseline; 1 week; and 1, 3, and 6 months after treatment. Epidermal melanin quantification was performed on 10 biopsy samples and compared before and after treatment. RESULTS: All patients showed improvement by mMASI scores, range (21%-75%) compared with that at baseline. No permanent side effects occurred. The recurrence rate was 81%. By histopathology, a slight, nonsignificant (p = .305) decrease in melanin deposition was seen in all layers of the epidermis 1 week after the laser treatments ended. CONCLUSION: The results confirm the safety and effectiveness of low-fluence QS Nd:YAG laser for treating melasma; however, the high recurrence suggests poor long-term results when the laser is used as a monotherapy.