Actinic keratoses (AK) are precancerous lesions that can progress to squamous cell carcinoma. Photodynamic therapy (PDT) and topical 5-fluorouracil (5FU) are commonly used agents for AK. Empirical reports suggest that combining them can improve the therapeutic response. However, the optimal combined regimen was not clear in terms of proper sequence, timing, and mechanism. This clinical study explored mechanisms of action for neoadjuvantal 5FU and PDT for treatment of AK. A bilaterally controlled trial (17 patients) was performed. One side of the body (face, scalp, forearms) received 5FU pretreatment for 6 days, whereas the other side served as no-pretreatment control. Methylaminolevulinate cream was applied to both sides for 3 hours, and protoporphyrin IX (PpIX) levels were measured by noninvasive fluorimetry and skin biopsy. After red light illumination, lesion clearance was assessed at 3, 6, 9, and 12 months after PDT. PpIX levels were increased 2- to 3-fold in 5FU-pretreated lesions versus controls. Altered expression of heme-synthetic enzymes (coproporphyrinogen oxidase and ferrochelatase) and induction of p53 were observed, probably accounting for increased PpIX and subsequent cancer cell death. Relative clearance rates after PDT with or without 5FU pretreatment were 75% versus 45% at 3 months, and 67% versus 39% at 6 months, respectively; these differences were statistically significant. Serial 5FU and PDT improve AK clearance by at least two mechanisms, enhanced photosensitizer accumulation and p53 induction. Because 5FU and PDT are FDA-approved modalities, the combined regimen can be readily employed in clinical practice to reduce AK burden and reduce SCC risk. .

Cutaneous collagenous vasculopathy is a rare microangiopathy of superficial dermal blood vessels. Patients present with telangiectatic macules, predominantly on the extremities. A skin biopsy specimen is necessary to distinguish cutaneous collagenous vasculopathy from generalized essential telangiectasia. Microscopically, cutaneous collagenous vasculopathy resembles the superficial telangiectasias of generalized essential telangiectasia but additionally shows hyaline material in thickened vessel walls. The amorphous pink material is periodic acid-Schiff-positive and resistant to diastase. We describe a series of four patients with cutaneous collagenous vasculopathy and highlight its clinical and histopathologic features.

Abstract. Topical 5-aminolevulinic acid ͑ALA͒ is widely used in photodynamic therapy ͑PDT͒ of actinic keratoses ͑AK͒, a type of premalignant skin lesion. However, the optimal time between ALA application and exposure to light has not been carefully investigated. Our objective is to study the kinetics of protoporphyrin IX ͑PpIX͒ accumulation in AK after short contact ALA and relate this to erythemal responses. Using a noninvasive dosimeter, PpIX fluorescence measurements ͑5 replicates͒ were taken at 20-min intervals for 2 h following ALA application, in 63 AK in 20 patients. Data were analyzed for maximal fluorescent signal obtained, kinetic slope, and changes in erythema. Our results show that PpIX accumulation was linear over time, becoming statistically higher than background in 48% of all lesions by 20 min, 92% of lesions by 1 h, and 100% of lesions by 2 h. PpIX accumulation was roughly correlated with changes in lesional erythema post-PDT. We conclude that significant amounts of PpIX are produced in all AK lesions by 2 h. The linear kinetics of accumulation suggest that shorter ALA application times may be efficacious in many patients. Noninvasive fluorescence monitoring of PpIX may be useful to delineate areas of high PpIX accumulation within precancerous areas of the skin. © 2010 Society of Photo-Optical Instrumentation Engineers.

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