Actinic Keratoses: A Review of Clinical, Dermoscopic, and Therapeutic Aspects PDF

An Bras Dermatol. 2019;94(6):637---657 Anais Brasileiros de Dermatologia www.anaisdedermatologia.org.br CONTINUING MEDICAL EDUCATION Actinic keratoses: review...

An Bras Dermatol. 2019;94(6):637---657 Anais Brasileiros de Dermatologia www.anaisdedermatologia.org.br CONTINUING MEDICAL EDUCATION Actinic keratoses: review of clinical, dermoscopic, and therapeutic aspects!,!! Clarissa Prieto Herman Reinehr ∗ , Renato Marchiori Bakos Department of Dermatology, Hospital de Clínicas de Porto Alegre, Porto Alegre, RS, Brazil Received 17 February 2019; accepted 17 October 2019 Available online 6 November 2019 Abstract Actinic keratoses are dysplastic proliferations of keratinocytes with potential for KEYWORDS malignant transformation. Clinically, actinic keratoses present as macules, papules, or hyperk- Dermoscopy; eratotic plaques with an erythematous background that occur on photoexposed areas. At initial Keratosis, actinic; stages, they may be better identified by palpation rather than by visual inspection. They may Neoplasms, squamous also be pigmented and show variable degrees of infiltration; when multiple they then constitute cell; the so-called field cancerization. Their prevalence ranges from 11% to 60% in Caucasian indi- Precancerous viduals above 40 years. Ultraviolet radiation is the main factor involved in pathogenesis, but conditions; individual factors also play a role in the predisposing to lesions appearance. Diagnosis of lesions Skin neoplasms is based on clinical and dermoscopic examination, but in some situations histopathological anal- ysis may be necessary. The risk of transformation into squamous cell carcinoma is the major concern regarding actinic keratoses. Therapeutic modalities for actinic keratoses include top- ical medications, and ablative and surgical methods; the best treatment option should always be individualized according to the patient. © 2019 Sociedade Brasileira de Dermatologia. Published by Elsevier España, S.L.U. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/). History and definition Actinic keratoses, also called solar or senile keratoses, were described by Dubreuilh in 1826.1,2 Later, the term ‘‘keratoma senilis’’ was proposed by Freudenthal, and in ! How to cite this article: Reinehr CPH, Bakos RM. Actinic ker- 1958 Pinkus renamed the lesions as actinic keratoses.3 Although classically categorized as pre-neoplastic lesions, atoses: review of clinical, dermoscopic, and therapeutic aspects. some authors suggest considering them as in situ neo- An Bras Dermatol. 2019;94:637---57. !! Study conducted at the Department of Dermatology, Hospital plasms, since they derive from clonal DNA modifications de Clínicas de Porto Alegre, Porto Alegre, RS, Brazil. in keratinocytes.2,4---7 In this sense, actinic keratoses are ∗ Corresponding author. considered as having characteristics of malignancy since E-mail: [email protected] (C.P.H. Reinehr). their genesis, both from the standpoint of cytological https://doi.org/10.1016/j.abd.2019.10.004 0365-0596/© 2019 Sociedade Brasileira de Dermatologia. Published by Elsevier España, S.L.U. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/). 638 Reinehr CPH, Bakos RM alterations presented by epidermal keratinocytes, which are In Brazil, actinic keratoses represent the fourth most similar to those observed in spinocellular carcinomas (SCCs), common dermatological diagnosis.1 In addition, they rep- including loss of polarity, nuclear pleomorphism, dysreg- resent the main reason for dermatological consultation in ulated maturation, and increased number of mitoses, as Brazil in individuals over 65 years (17.2%); in Southern Brazil, well as from the molecular standpoint, presenting iden- this corresponds to 7.4% of the diagnoses and in the North tical mutations in the p53 protein.3 The difficulty in region, to 2.89% of visits.24 In a study conducted in Curitiba establishing unambiguous criteria for determining when with 491 patients, with a mean patient age of 59.8 years, an actinic keratosis undergoes SCC transformation rein- the prevalence of actinic keratosis was 60.79% in women and forces this hypothesis. According to Ackerman, there 30.9% in men.25 Another study, conducted in Bauru, evalu- is no clear threshold between actinic keratoses and ated the prevalence of actinic keratoses only in Japanese thin SCCs, and actinic keratosis are considered a part descendants living in Brazil; the study observed a prevalence of the evolutionary spectrum of SCC, described as an of 13.4%, with a mean age of 68.9 years; this prevalence is ‘‘embryonic’’ SCC.2 Therefore, proposed nomenclatures higher than that observed in individuals of the same ethnic replacing the term actinic keratosis would include ker- composition living in Japan.26 atinocytic intraepidermal neoplasia and intraepidermal As mentioned above, the prevalence of actinic keratoses solar keratotic SCC.3 increases according to the age of the patients, ranging from Actinic keratoses are formed by proliferation of ker-