Conjunctival keratoacanthoma

Keratoacanthoma is a rapidly growing skin neoplasia that may stabilize or regress spontaneously. We describe here a case of conjunctival keratoacanthoma and comment about the clinical signs and symptoms and pathological findings.

Association between solitary keratoacanthoma and cigarette smoking: A case-control study

Solitary keratoacanthoma (KA) is a common benign epithelial tumor of the skin characterized by rapid growth and a tendency toward spontaneous regression. The exact etiology and classification of KA are a matter of debate. Smokers also seem to be more affected than persons who never smoke. The objective of this study was to evaluate the association between solitary KA and smoking habit. A case-control study involving 78 patients diagnosed with KA and 199 controls from the related community was performed to evaluate the association between cigarette smoking and KA. A higher smoking prevalence was noted in cases (69.2 %) than controls (21.6 %) and the odds ratio adjusted for sex and age was 9.1 (95 % CI 4.9 to 17.1, p< 0.01). The mean tumoral diameter at surgery and the site of involvement was not statistically related to smoking. These findings suggest that cigarette smoking is associated with the development of KA. © 2006 Dermatology Online Journal.

Expression of apoptotic and cell proliferation regulatory proteins in keratoacanthomas and squamous cell carcinomas of the skin

The aim of this study was to investigate the expression of p53, caspase-3, bcl-2, MIB-1, and PCNA to validate more objective methods to differentiate squamous cell carcinoma and keratoacanthoma, as well as to understand their pathogenesis with accuracy. A total of 52 cases of histopathologically diagnosed keratoacanthoma in the proliferative stage and 56 cases of well-differentiated squamous cell carcinoma were selected in this study. The expression was evaluated by means of immunohistochemistry. Bcl-2 immunoreactivity was weak or absent in the majority of cases, either in squamous cell carcinoma or in keratoacanthoma. PCNA-positive cells did not show differences between two lesions evaluated. on the other hand, MIB-1 was statistically significant (p<0.05) between squamous cell carcinomas and keratoacanthomas. Moreover, p53 and caspase-3 were overexpressed in squamous cell carcinomas. Together, these results suggest that the biological behavior of the well-differentiated squanous cell carcinomas of the skin may be associated with cellular proliferation and/or deregulation of cell death, indicated by increased expression of the MIB-1 and apoptotic proteins p53 and caspase-3, respectively. (C) 2007 Elsevier GrnbH. All rights reserved.

Detecção e genotipagem de papilomavírus humano em lesões de queratoacantoma solitário de pacientes imunocompetentes

FUNDAMENTOS: O queratoacantoma é neoplasia cutânea benigna que incide preferencialmente em indivíduos de pele clara, faixa etária elevada, acometendo áreas fotoexpostas. Além da exposição à radiação ultravioleta, sua etiologia é relacionada a diversos carcinógenos, entre eles a infecção pelo papilomavírus humano (HPV). OBJETIVOS: Avaliar a prevalência do DNA do HPV, bem como seus genótipos, em lesões de queratoacantoma solitário de pacientes imunocompetentes. MÉTODOS: Foram estudados queratoacantomas de pacientes sem evidências de imunocomprometimento, excisados entre 1996 e 2000 em hospital universitário. Realizaram-se cortes histológicos, desparafinização e extração de DNA desses fragmentos. Os espécimes positivos para DNA de HPV foram submetidos ao seqüenciamento gênico, para determinação do genótipo. RESULTADOS: Foram estudados 58 pacientes com idade média de 64,5±13,8 anos. A proporção entre os sexos foi semelhante, e as localizações mais comuns foram os membros superiores (50%) e a face (27,6%). Detectou-se DNA de HPV em 48 (82,7%) fragmentos de queratoacantomas, sendo os genótipos 6, 11 e 16 os prevalentes. CONCLUSÕES: A alta prevalência do achado de DNA de HPV em lesões de queratoacantoma solitário pode sugerir a participação viral em sua oncogênese.