Topical photodynamic therapy (PDT) using daylight is effective in the treatment of actinic keratoses (AKs), offering the potential for treatment of large fields such as full face and balding scalp, but with minimal therapy-associated pain. Comparison with conventional PDT indicates similar efficacy for thin and moderate-thickness AKs, but with significantly less discomfort/pain, driving a patient preference for daylight-mediated PDT (DL-PDT) compared with conventional PDT using high-intensity office/hospital-based light sources. Treatment protocol involves the application of a photosensitizing agent without occlusion and subsequent exposure to ambient daylight within 30 min, with patients exposed to daylight for 1.5-2.0 h. Pivotal randomized controlled trials in Europe and Australia have confirmed the efficacy of methyl aminolevulinic acid (MAL) DL-PDT in comparison with conventional MAL-PDT for mild and moderate-thickness lesions on the face and scalp. Initial clearance rates of 70-89% are reported. DL-PDT using a nanoemulsion aminolevulinic acid (ALA) has recently been shown to be at least as effective as MAL DL-PDT in treating mild and moderate-thickness AKs. DL-PDT may offer a better-tolerated method for treating patients with extensive AK disease. There is emerging literature on the potential for field PDT to reduce the number of new AKs developing, potentially preventing/slowing skin cancer development. Conventional PDT remains established as a therapy for Bowen's disease (squamous cell carcinoma in situ), superficial and certain thin basal cell carcinomas (BCCs), and AKs. The evidence for the use of DL-PDT beyond AK is limited, although has been reported in actinic cheilitis, superficial BCC, and acne and cutaneous leishmaniasis. There is emerging interest in combination therapy for AK, using one or more field therapies such as DL-PDT as an option to complement with localized treatment for residual lesions. We review current recommendations and consider the appropriate place for DL-PDT in our treatment armamentarium.

Sclerosing squamous cell carcinoma (SCC), also known as "desmoplastic" SCC, is a rare subtype of cutaneous malignancy. This variant is clinically significant because it is associated with an increased risk of local recurrence and metastasis. We herein present 16 examples of sclerotic SCC of the skin in 8 men and 3 women, with a median age of 66 years. The most common site of origin for this tumor is the skin of the head and neck, including the scalp (5 tumors in 2 different patients), forehead (3 cases), nasal ala (2 cases), neck (2 cases in the same patient), ear (2 cases), cheek (1 case), and chest (1 case). Microscopically, sclerosing SCCs are characterized by cellular cords, nests, and islands, as well as scattered single cells infiltrating densely desmoplastic and collagenized connective tissue. The differential diagnosis principally includes sclerosing basal cell carcinoma, microcystic adnexal carcinoma, and desmoplastic trichoepithelioma. The main goals of this study are to further characterize these lesions pathologically, and increase general awareness of this SCC subtype.

Photodynamic therapy (PDT) is an attractive treatment option for actinic keratoses (AKs), as large skin areas can be treated with high response rates and superior cosmetic outcome. The efficacy of 5-aminolevulinic acid (ALA)-PDT and methyl aminolevulinate (MAL)-PDT for AK has been proven in multiple studies, and this treatment is recommended in numerous consensus works and therapy guidelines. Moreover, a self-adhesive ALA patch has been approved for the PDT of AK. In a phase III study, ALA-patch-PDT was superior to cryotherapy and placebo in the treatment of mild to moderate AK on the face and scalp, and pre-treatment of the lesions and additional light occlusion was unnecessary when using the patch. ALA with a proprietary nanoemulsion is another newly marketed ALA gel that has been approved for the treatment of mild to moderate AK on the head. ALA was combined with a nanoemulsion to achieve increased chemical stability of the active ingredient and to enhance skin penetration. One study found that ALA was superior to MAL in the treatment of AK on the face or scalp. Daylight-PDT is a simpler and more tolerable treatment procedure for PDT, and three randomised studies have shown that daylight-PDT is an effective and pain-free treatment for AK; however, the procedure is limited by the need for a sufficient light dose and outdoor temperature. Ablative fractional laser resurfacing prior to MAL has been used to improve the PDT response of thick AK. However, more intense acute skin reactions and long-term adverse events in ablative fractional laser resurfacing-PDT compared with PDT-treated skin were found, which might limit the use of the intensified treatment.