Squamous cell carcinoma on the scalp following treatment with 5% imiquimod cream

Rare Cutaneous Side Effects of Imiquimod: A Review on Its Mechanisms, Diagnosis, and Management

As an immune-response modifier, imiquimod can bind to Toll-like receptors on immune cells and enhance innate and adaptive immune responses, exerting potential antitumor and antiviral effects, which led to its approval by the US Food and Drug Administration for the treatment of actinic keratosis, superficial basal cell carcinomas, and anogenital warts, and to its off-label use in treating many other benign and malignant dermatoses. Although topical administration of imiquimod has been considered well tolerated, an increasing number of cutaneous and noncutaneous side effects are being reported as its clinical applications expand. This review primarily focuses on rare cutaneous side effects. To the best of our knowledge, this is the first article to summarize the mechanism, diagnosis, and management of rare cutaneous side effects of imiquimod, which may help to heighten awareness among physicians, especially dermatologists, about potential imiquimod-induced cutaneous side effects.

Safety of topical interventions for the treatment of actinic keratosis

Introduction: Actinic keratosis (AK) are proliferations of atypical keratinocytes that may eventually progress to cutaneous squamous cell carcinoma. Therefore, AK requires consequent and early treatment. Areas covered: A variety of effective approaches is currently available for the clearance of AK. These interventions may be applied either in a lesion-directed or field-directed mode as AK can occur as single or multiple lesions. Field-directed approaches typically comprise topical drug-mediated interventions which aim at eliminating all visible lesions and also at clearing subclinical changes of the actinically damaged field. However, most treatment options are associated with local adverse events such as erythema, scaling, pain, and rarely with systemic symptoms. This expert review provides a comprehensive and up-to-date overview of the safety considerations of the commonly prescribed topical treatment agents cyclooxygenase inhibitors, 5-fluorouracil, imiquimod, ingenol mebutate, and photodynamic therapy. All these therapies have been proven efficient, yet they differ considerably regarding their safety profile. Expert opinion: In the future, safety concerns will relate to long-term and irreversible adverse drug events instead of application site reactions. In particular, the rate of treatment-associated non-melanoma skin cancers will increasingly come into focus and warrant investigation in postmarketing surveillance trials with a long-term follow-up.

PGP 9.5 and Cyclin D1 Coexpression in Cutaneous Squamous Cell Carcinomas

Background: squamous cell carcinoma (SCC) consists of altered keratinocytes, presents variable differentiation, inexorably progresses, and on occasion metastasizes. Objective: to investigate the biological activity of epidermal cells in SCCs by estimating the expression of PGP 9.5 and cyclin D1 using immunohistochemistry. Methods: the sample included 13 well-differentiated cases of cutaneous SCC (grade I), 12 moderately differentiated tumors (grade II), and 7 poorly differentiated lesions (grade III). Four cases belonged to the distinct entity of pseudoadenoid SCC. Results: PGP 9.5 expression was positively correlated with tumor stage ( P < .001) and potential perineural invasion ( P < .001), whereas cyclin D1 expression correlated inversely with the degree of cellular differentiation ( P < .001) and PGP 9.5 immunostaining ( P < .001). Conclusion: PGP 9.5 and cyclin D1 coexpression was closely associated with tumor aggressiveness and can be classified as a marker for predicting the outcome of resection-treated skin cancer patients.