The endemic wildflower, Geleznowia verrucosa Turcz. (Rutaceae), is widely distributed as small disjunct populations throughout the sandplains of Western Australia (21 degrees 50'S, 116 degrees 12'E to 31 degrees 12'S, 117 degrees 02'E). Although the morphological forms can be genus is supposedly monospecific, three recognised in the field:(1) a small form (0.5-1 m) with small, often solitary flowers and small leaves;(2) a large form (1-2 m) with larger, more abundant flowers and larger leaves; and,(3) an intermediate form exhibiting mixed morphological characters.The patterns of morphological, reproductive and genetic variation within and between populations of these three forms were investigated. Uni- and multivariate analyses of morphological traits found the large and intermediate forms to be closely allied, and distinguishable from the small form. Responses to controlled pollination experiments indicated that the small form favours selfing but maintains some level of outcrossing, while the large form exhibits a mixed mating system. The intermediate form displays a stronger self-pollination mechanism than the small form.Patterns of genetic variation were analysed using both allozymes and randomly amplified polymorphic DNA (RAPDs). The allozyme analysis concurred with genetically depauperate expectations of endemic taxa (A, 1.4; P, 29.6%; H(subscript)0, 0.055; H(subscript)e, 0.097). Genetic diversity and patterns of allelic distribution, however, differed within the three forms. Lower levels of genetic diversity were found in the small form (H(subscript)T,0.192) compared with the large form (H(subscript)T, 0.254), although both forms apportioned this diversity within populations (H(subscript)S, 0.122 and 0.164, respectively) rather than between D(subscript)ST, 0.070 and 0.090, respectively). In contrast, populations of the intermediate form are highly divergent ++ / (G(subscript)ST, 54%), with genetic diversity apportioned between populations (D(subscript)ST, 0.121) rather than within (H(subscript)S, 0.105). Whereas the morphometric analyses had indicated closer affinity between the large and intermediate forms, both allozyme and RAPD analyses suggested that the intermediate form is closer to the small form than to the large form.There is circumstantial evidence to suggest that the intermediate form has arisen following hybridisation between the small and large forms. Its hybrid origin is supported by the high level of genetic diversity between the intermediate form populations, as well as its strong autogamous tendencies and mixed morphological characteristics. In a putative zone of hybridisation between the small and large forms, asymmetric introgression was observed, indicating gene exchange between the two forms can occur when they come into contact.It is speculated that three major events have shaped the evolution of Geleznowia verrucosa and contributed to hybridisation between the small and large forms. Firstly, the small form is derived from the large form; associated with this speciation was a shift in reproductive strategy from outcrossing to selfing when the small form migrated into a harsher and more unpredictable environment. Secondly, recurrent Tertiary and Quaternary climatic perturbations have facilitated range expansion and contraction of these forms, generating opportunities for spatially and temporally distributed hybridisation events. Finally, more recent evolution has been driven by population disjunction, limited gene flow, and bottleneck and/or associated founder effects.From this study it is apparent that the genus Geleznowia consists of at least two taxa and a series of hybrid derivatives. On this basis, formal systematic revision of the genus is now warranted. Systematic clarification will also assist ++ / with the conservation and management of this valuable natural resource, which is currently under threat.

Field studies were used to characterize habitat and evaluate morphological characters of Carex glaucescens, C. joorii and C. verrucosa. Morphometric analysis of herbarium specimens along with field studies, Environmental Scanning Electron Microscopy (ESEM), pollen viability and phenology show C. glaucescens, C. joorii and C. verrucosa to be taxonomically distinguishable at the species level. The taxonomy of Carex section Glaucescentes is presented in an artificial dichotomous key to the taxa and in species descriptions.

Universiẗat, Diss., 2003--Bonn.

Carcinoma verrucoso e leucoplasia verrucosa proliferativa, estão entre as lesões que apresentam difícil diagnóstico diferencial devido às semelhanças histopatológicas que ocorrem em determinada fase de evolução. Existe, para tanto, a necessidade de somar dados clínico-epidemiológicos ao histopatológico a fim de se estabelecer o diagnóstico final. A leucoplasia verrucosa proliferativa caracteriza-se por seu acometimento multifocal, grande potencial de recidiva e perfil progressivo que resulta em alto risco de transformação maligna. Por outro lado, o carcinoma verrucoso, variante de baixo grau do carcinoma epidermoide, é unifocal e dificilmente recidiva. A importância de novos estudos acerca das suas duas lesões mencionadas vem a agregar conhecimento de modo a facilitar um correto diagnóstico e, consequentemente, um apurado prognóstico. A leucoplasia verrucosa proliferativa, por se tratar de lesão com alto potencial de transformação maligna, pode evoluir para carcinoma epidermoide invasivo, menos diferenciado e mais agressivo com consequente prognostico obscuro, ao passo que, o carcinoma verrucoso não incorre em metástases e apresenta um prognóstico mais favorável. Isso posto, com o objetivo de aumentar a precisão diagnóstica, o presente trabalho propôs identificar e quantificar em porcentagem os critérios histopatológicos encontrados na leucoplasia verrucosa proliferativa e no carcinoma verrucoso visando diferenciar morfologicamente as lesões dos dois grupos. Também buscamos comparar os dados epidemiológicos referentes aos casos inseridos no estudo, dentre eles vinte e dois casos de leucoplasia verrucosa proliferativa, dezoito casos de carcinoma verrucoso e dois casos apresentando tanto leucoplasia verrucosa proliferativa quanto carcinoma verrucoso, casos esses com diagnósticos estabelecidos previamente (baseando-se nos dados epidemiológicos somados ao histopatológico). A utilização de um marcador imuno-histoquímico da atividade proliferativa celular, o Ki67, também permitiu uma análise comparativa entre o comportamento biológico de ambas as lesões através de um ensaio quantitativo e qualitativo. A marcação mostrou-se escassa, mas evidente em células mitóticas da leucoplasia verrucosa proliferativa, mostrando, no entanto, maior número de células positivas no carcinoma verrucoso, estas visíveis nas camadas basal e parabasal. Os resultados do presente trabalho permitiram concluir então que o marcador Ki67 pode auxiliar no diagnóstico diferencial entre leucoplasia verrucosa proliferativa e carcinoma verrucoso. Foi possível depreender também que, histologicamente, o carcinoma verrucoso apresenta maior alteração em sua conformação epitelial, bem como maior número de atipias cito-arquiteturais quando comparado à leucoplasia verrucosa proliferativa, que, apesar de seu aspecto morfológico, evolui no sentido de uma potencial transformação maligna, apresentando, por sua vez, maior freqüência de projeções em gota. / Verrucous carcinoma and proliferative verrucous leukoplakia, are among the injuries presenting difficult differential diagnosis due to histopathological similarities that occur at some stage of evolution. There is a need to add clinical, epidemiological and histopathological data to achieve the final diagnosis. Proliferative verrucous leukoplakia is characterized by its multifocal involvement, great potential for relapse and progressive profile that results in malignant transformation high risk. On the other hand, the verrucous carcinoma, which is considered low-grade variant of squamous cell carcinoma, is unifocal and unlikely to return. The importance of new studies on its two mentioned lesions is to generate knowledge aiming at a correct diagnosis and prognosis. The proliferative verrucous leukoplakia, since it is a lesion with high potential for malignant transformation, can develop into less differentiated and more aggressive invasive squamous cell carcinoma with subsequent poor prognosis, whereas the verrucous carcinoma incurs no metastases and presents a more favorable prognosis. Thus, aimed to increase the diagnostic accuracy, the present work looked for to identify and quantify in percentage the histopathological criteria found on proliferative verrucous leukoplakia and verrucous carcinoma, aiming morphologically differentiate the lesions from both groups. We also seek to compare the epidemiological data related to cases included in the study, including twenty-two cases of proliferative verrucous leukoplakia, eighteen cases of verrucous carcinoma and two cases showing both proliferative verrucous leukoplakia as verrucous carcinoma, cases with these diagnoses established previously (based on epidemiological data added to histopathology data). Using a cell proliferation immunohistochemical marker, Ki67, we made a comparative analysis between the biological behavior of both lesions by quantitative and qualitative assay. We saw a few strongly positive mitotic cells in samples of proliferative verrucous leukoplakia, and numerous positive cells observed in the basal and parabasal layers of verrucous carcinoma samples. This study results indicate, then, that the Ki67 marker may help in the differential diagnosis between proliferative verrucous leukoplakia and verrucous carcinoma. It was also possible to conclude that, histologically, the verrucous carcinoma shows greater change in its epithelial conformation and a higher number of cyto-architectural atypia when compared to proliferative verrucous leukoplakia, which, despite its morphological appearance, evolves towards a potential malignant transformation, presenting, in turn, higher drop-shaped rete ridges frequency.

Carcinoma verrucoso e leucoplasia verrucosa proliferativa, estão entre as lesões que apresentam difícil diagnóstico diferencial devido às semelhanças histopatológicas que ocorrem em determinada fase de evolução. Existe, para tanto, a necessidade de somar dados clínico-epidemiológicos ao histopatológico a fim de se estabelecer o diagnóstico final. A leucoplasia verrucosa proliferativa caracteriza-se por seu acometimento multifocal, grande potencial de recidiva e perfil progressivo que resulta em alto risco de transformação maligna. Por outro lado, o carcinoma verrucoso, variante de baixo grau do carcinoma epidermoide, é unifocal e dificilmente recidiva. A importância de novos estudos acerca das suas duas lesões mencionadas vem a agregar conhecimento de modo a facilitar um correto diagnóstico e, consequentemente, um apurado prognóstico. A leucoplasia verrucosa proliferativa, por se tratar de lesão com alto potencial de transformação maligna, pode evoluir para carcinoma epidermoide invasivo, menos diferenciado e mais agressivo com consequente prognostico obscuro, ao passo que, o carcinoma verrucoso não incorre em metástases e apresenta um prognóstico mais favorável. Isso posto, com o objetivo de aumentar a precisão diagnóstica, o presente trabalho propôs identificar e quantificar em porcentagem os critérios histopatológicos encontrados na leucoplasia verrucosa proliferativa e no carcinoma verrucoso visando diferenciar morfologicamente as lesões dos dois grupos. Também buscamos comparar os dados epidemiológicos referentes aos casos inseridos no estudo, dentre eles vinte e dois casos de leucoplasia verrucosa proliferativa, dezoito casos de carcinoma verrucoso e dois casos apresentando tanto leucoplasia verrucosa proliferativa quanto carcinoma verrucoso, casos esses com diagnósticos estabelecidos previamente (baseando-se nos dados epidemiológicos somados ao histopatológico). A utilização de um marcador imuno-histoquímico da atividade proliferativa celular, o Ki67, também permitiu uma análise comparativa entre o comportamento biológico de ambas as lesões através de um ensaio quantitativo e qualitativo. A marcação mostrou-se escassa, mas evidente em células mitóticas da leucoplasia verrucosa proliferativa, mostrando, no entanto, maior número de células positivas no carcinoma verrucoso, estas visíveis nas camadas basal e parabasal. Os resultados do presente trabalho permitiram concluir então que o marcador Ki67 pode auxiliar no diagnóstico diferencial entre leucoplasia verrucosa proliferativa e carcinoma verrucoso. Foi possível depreender também que, histologicamente, o carcinoma verrucoso apresenta maior alteração em sua conformação epitelial, bem como maior número de atipias cito-arquiteturais quando comparado à leucoplasia verrucosa proliferativa, que, apesar de seu aspecto morfológico, evolui no sentido de uma potencial transformação maligna, apresentando, por sua vez, maior freqüência de projeções em gota. / Verrucous carcinoma and proliferative verrucous leukoplakia, are among the injuries presenting difficult differential diagnosis due to histopathological similarities that occur at some stage of evolution. There is a need to add clinical, epidemiological and histopathological data to achieve the final diagnosis. Proliferative verrucous leukoplakia is characterized by its multifocal involvement, great potential for relapse and progressive profile that results in malignant transformation high risk. On the other hand, the verrucous carcinoma, which is considered low-grade variant of squamous cell carcinoma, is unifocal and unlikely to return. The importance of new studies on its two mentioned lesions is to generate knowledge aiming at a correct diagnosis and prognosis. The proliferative verrucous leukoplakia, since it is a lesion with high potential for malignant transformation, can develop into less differentiated and more aggressive invasive squamous cell carcinoma with subsequent poor prognosis, whereas the verrucous carcinoma incurs no metastases and presents a more favorable prognosis. Thus, aimed to increase the diagnostic accuracy, the present work looked for to identify and quantify in percentage the histopathological criteria found on proliferative verrucous leukoplakia and verrucous carcinoma, aiming morphologically differentiate the lesions from both groups. We also seek to compare the epidemiological data related to cases included in the study, including twenty-two cases of proliferative verrucous leukoplakia, eighteen cases of verrucous carcinoma and two cases showing both proliferative verrucous leukoplakia as verrucous carcinoma, cases with these diagnoses established previously (based on epidemiological data added to histopathology data). Using a cell proliferation immunohistochemical marker, Ki67, we made a comparative analysis between the biological behavior of both lesions by quantitative and qualitative assay. We saw a few strongly positive mitotic cells in samples of proliferative verrucous leukoplakia, and numerous positive cells observed in the basal and parabasal layers of verrucous carcinoma samples. This study results indicate, then, that the Ki67 marker may help in the differential diagnosis between proliferative verrucous leukoplakia and verrucous carcinoma. It was also possible to conclude that, histologically, the verrucous carcinoma shows greater change in its epithelial conformation and a higher number of cyto-architectural atypia when compared to proliferative verrucous leukoplakia, which, despite its morphological appearance, evolves towards a potential malignant transformation, presenting, in turn, higher drop-shaped rete ridges frequency.

Múltiplas lesões orais que progridem em um curso irreversível lento mediante expansão de áreas afetadas, no sentido de um pior prognóstico, caracterizam a leucoplasia verrucosa proliferativa. A referida lesão apresenta perfil agressivo circunstanciando indeterminado número de recidivas e alto potencial de transformação neoplásica. A tal fato, se atribui a frequente incidência em carcinoma verrucoso bem como em carcinoma espinocelular de boca invasivo e potencialmente metastático, inserindo-se este em índices de maior prevalência quando comparado ao carcinoma verrucoso em pacientes com leucoplasia verrucosa proliferativa. Vincula-se ao contexto supracitado, o envolvimento de vias de sinalização celular ocasionando o desarranjo de um complexo sistema o qual abarca atividade de oncogenes, inibição de genes supressores de tumor e alteração de reguladores do sistema de reparo do DNA, encerrando-se, por sua vez, em diversos fatores favoráveis à carcinogênese, dentro os quais a regulação negativa de cascatas pró-apoptóticas e estímulo à proliferação celular desordenada. A este processo se pode relacionar o desconcerto da via PI3K/Akt/mTOR e de um membro do complexo de pré-replicação, o MCM3. Para tanto, a análise pormenorizada do perfil evolutivo da lesão por meio do rol de diagnósticos pregressos, bem como por meio do cruzamento de dados epidemiológicos, além da caracterização de neoplasias malignas provenientes da leucoplasia verrucosa proliferativa por meio da expressão dos biomarcadores pAkt, pmTOR e MCM3, vêm a explanar aspectos ainda pouco estudados desta intrigante entidade clinicopatológica. Neste sentido, o presente trabalho analisou o histórico diagnóstico de 28 pacientes com leucoplasia verrucosa proliferativa submetendo à análise imuno-histoquímica para as supracitadas proteínas, o montante de 34 amostras dos mesmos pacientes, integrando estas, 28 de leucoplasia verrucosa proliferativa, 4 de carcinoma verrucoso e 2 de carcinoma espinocelular. Dos resultados obtidos, foi possível depreender a prevalência de lesões em mucosa jugal, rebordo alveolar e língua confirmando ainda seu perfil evolutivo em face às múltiplas lesões com alto potencial recidivante e latente insurgir do carcinoma espinocelular, este podendo ainda ser embasado por expressiva marcação de pmTOR, pAkt e MCM3. / Multiple oral lesions that progress in a slow irreversible course by expansion of affected areas, in the sense of a worse prognosis, characterize proliferative verrucous leukoplakia. The said lesion presents an aggressive profile, with an indeterminate number of recurrences and a high potential for neoplastic transformation. To this fact, it is attributed to frequent incidence in verrucous carcinoma as well as invasive and potentially metastatic invasive mouth squamous cell carcinoma, inserting itself in indices of higher prevalence when compared to verrucous carcinoma in patients with proliferative verrucous leukoplakia. It is linked to the aforementioned context, the involvement of cell signaling pathways, causing the disruption of a complex system which encompasses oncogenes activity, inhibition of tumor suppressor genes and alteration of DNA repair system regulators, ending in several factors favorable to carcinogenesis, in which negative regulation of pro-apoptotic cascades and stimulation to disordered cell proliferation. To this process one may relate the dissatisfaction of the PI3K / Akt / mTOR pathway and a member of the pre-replication complex, MCM3. Thus, the detailed analysis of the evolutionary lesion profile through the role of previous diagnoses and the cross-referencing of epidemiological data, as well as the characterization of malignant neoplasms from proliferative verrucous leukoplakia by the expression of the biomarkers pAkt, pmTOR and MCM3, come to clarify aspects that have not yet been studied in this intriguing clinicopathological entity. Thus, the present study analyzed the historical diagnosis of 28 patients with proliferative verrucous leukoplakia submitting to immunohistochemical analysis for the aforementioned proteins, the amount of 34 samples from the same patients, comprising 28 of proliferative verrucous leukoplakia, 4 of verrucous carcinoma and 2 of squamous cell carcinoma. From the results obtained, it was possible to detect the prevalence of lesions in the buccal mucosa, alveolar ridge and tongue, and the confirmation of its evolutionary profile in the face of the multiple lesions with high recurrent and latent insurgent potential of squamous cell carcinoma, which may be supported by a significant mark of pmTOR, pAkt and MCM3.

Looking at the metabolite profile of an organism provides insights into the metabolomic state of a cell and hence also into pathways employed. Little is known about the metabolites produced by corals and their algal symbionts. In particular, corals from the central Red Sea are understudied, but interesting study objects, as they live in one of the warmest and most saline environments and can provide clues as to the adjustment of corals to environmental change. In this study, we applied gas chromatography – mass spectrometry (GC–MS) metabolite profiling to analyze the metabolic profile of four coral species and their associated symbionts: Fungia granulosa, Acropora hemprichii, Porites lutea, and Pocillopora verrucosa. We identified and quantified 102 compounds among primary and secondary metabolites across all samples. F. granulosa and its symbiont showed a total of 59 metabolites which were similar to the 51 displayed by P. verrucosa. P. lutea and A. hemprichii both harbored 40 compounds in conjunction with their respective isolated algae. Comparing across species, 28 metabolites were exclusively present in algae, while 38 were exclusive to corals. A principal component and cluster analyses revealed that metabolite profiles clustered between corals and algae, but each species harbored a distinct catalog of metabolites. The major classes of compounds were carbohydrates and amino acids. Taken together, this study provides a first description of metabolites of Red Sea corals and their associated symbionts. As expected, the metabolites of coral hosts differ from their algal symbionts, but each host and algal species harbor a unique set of metabolites. This corroborates that host-symbiont species pairs display a fine-tuned complementary metabolism that provide insights into the specific nature of the symbiosis. Our analysis also revealed aquatic pollutants, which suggests that metabolite profiling might be used for monitoring pollution levels and assessing environmental impact.

Niche partitioning is a major component in understanding community ecology and how ecologically similar species coexist. Temporal and spatial partitioning and differences in foraging strategy, including sensitivity to risk (variance), likely contribute to partitioning as well. Here, we approach this partitioning with fine resolution to investigate differences in overall strategy between two species of diurnal, orb-weaving spiders, Verrucosa arenata and Micrathena gracilis (Araneae: Araneidae), that share similar spatial positioning, temporal foraging window, and prey. Through field observation, we found that V. arenata individuals appear to increase spatial and temporal sampling to compensate for an overall risk-prone strategy that depends on the interception and active capture of rare, large prey. Conversely, M. gracilis individuals employ a risk-averse strategy relying on passive capture of small but abundant prey consumed alongside the orb. We have thus identified how differing risk-sensitive foraging strategies may contribute to niche partitioning between otherwise similar species.

Niche partitioning is a major component in understanding community ecology and how different species divide limited environmental resources, enabling them to coexist. Temporal niche partitioning has been widely studied in a broad sense, such as in species that forage on similar nutritional sources dividing activity along diurnal and nocturnal classifications. Here, we approach this temporal niche partitioning with higher resolution to investigate partitioning between species within the same broad temporal and foraging niche. Two species of diurnal orb-weaving spiders (Araneae: Araneidae), Verrucosa arenata and Micrathena gracilis, both construct their orbs in spatially similar locations throughout the understory of deciduous forests in the morning, forage on flying insects throughout the day, and retreat in the evening. However, despite consisting of what appear to be roughly similar total lengths of adhesive silk in the capture spiral, overall orb structure is starkly different: V. arenata orbs are relatively large in diameter and sparse with capture threads; M. gracilis orbs, condensed in diameter and tightly coiled. What other differences might distinguish foraging strategy within this same niche? With extensive observation in their natural environment, we have found that these two species employ two distinct strategies by modulating behavior and orb structure: V. arenata construct orbs earlier in the day, resulting in a longer foraging period. However, V. arenata webs are more likely to be destroyed during the day such that there is a higher variance in foraging duration in V. arenata. We also found that V. arenata actively capture and consume more large prey and that M. gracilis more passively capture and consume small prey more reliably. These data suggest that these species have evolved different foraging strategies with V. arenata being risk-prone and M. gracilis being risk-averse. This study provides a more nuanced analysis of niche partitioning between species occupying otherwise similar temporal, habitat, and foraging niches.

A leucoplasia verrucosa proliferativa (LVP) é classificada como um subtipo da leucoplasia oral (LO), de rara incidência e alto potencial de malignização. Acomete com maior frequência pacientes do gênero feminino, acima da sétima década de vida e apresenta altos índices de recorrência após a realização de qualquer modalidade de tratamento. Seu aspecto clínico inicial é caracterizado pela presença de lesão branca, homogênea, aparentemente inócua, que desenvolve áreas eritematosas, superfície verrucosa, comportamento agressivo e envolvimento multifocal com o passar do tempo. A evolução clínica é geralmente lenta, levando anos para que ocorra transformação maligna. Existem divergências na literatura quanto aos critérios utilizados em seu diagnóstico. Alguns autores preconizam aqueles descritos em seu primeiro relato em 1985, que exigiam o acompanhamento das lesões desde sua fase inicial até o desenvolvimento de áreas verrucosas enquanto outros acreditam que o aguardo de fases avançadas apenas atrasa o diagnóstico e a instituição de tratamentos, aumentando as chances de malignização e piora do prognóstico dos pacientes. O objetivo desse estudo foi avaliar as características clínicas e demográficas dos indivíduos diagnosticados com LVP e compará-las a de pacientes diagnosticados com LO. Também foi realizada uma revisão e discussão dos critérios diagnósticos encontrados na literatura. Em nosso estudo analisamos retrospectivamente prontuários de pacientes diagnosticados na Disciplina de Estomatologia da FOUSP. Foram encontrados 9 pacientes diagnosticados com LVP, no período de 2007 a 2011, e 29 com LO, entre 1997 e 2011. Observamos que a LVP apresentou maior incidência em pacientes do gênero feminino, sem hábitos de tabagismo ou etilismo, com idade média de 73 anos. Já dentre os indivíduos com LO não encontramos diferença entre o envolvimento dos gêneros feminino e masculino, a idade média foi 57 anos e a maioria era tabagista ou etilista. O tempo médio de evolução da LVP foi de 5,4 anos enquanto da LO foi de 19,6 meses. Clinicamente, nenhum dos pacientes com LVP apresentou lesão homogênea inicial, sendo que todas eram multifocais, de comportamento agressivo e disseminado, com aspecto que variava desde placas brancas lisas até as nãohomogêneas, de superfície verrucosa, papilífera, com áreas eritematosas. Os pacientes com LO apresentavam lesões uni e multifocais localizadas, sendo que a maioria possuía placas brancas, de aspecto homogêneo. O grupo da LVP demonstrou taxas mais altas de recidiva em comparação as LO. A exigência de se acompanhar a lesão desde sua fase inicial e desconsiderar aquelas que apresentam aspecto multifocal na primeira consulta pode levar ao diagnóstico errôneo de uma verdadeira LVP, assim como aguardar o desenvolvimento de áreas verrucosas pode causar atraso considerável no diagnóstico, levando a tratamentos tardios e piorando o prognóstico do paciente. Sugerimos que dentre os critérios de diagnóstico da LVP devam ser considerados a presença de lesões brancas multifocais, lesões de comportamento agressivo, longo período de evolução, recorrência após qualquer forma de tratamento e não necessariamente apresentem aspecto verrucoso no momento do diagnóstico. / The proliferative verrucous leukoplakia (PVL) is a rare entity and was classified as a subtype of oral leukoplakia (OL). It affects more commonly elderly females and tends to recur after any type of treatment. Initially, it presents inconspicuous white lesions that progress to non-homogenous areas and develop verrucous surface, aggressive behavior and multifocal involvement over time. The lesions show a high tendency to transform into squamous cell carcinomas, usually taking years or decades to develop malignancy. There are controversies in the literature regarding the diagnostic criteria for PVL. Some authors follow those proposed on the first PVL report in 1985 which claimed continued follow-up since initial stages until the development of verrucous areas. Others believe that waiting for later stages postpone the diagnosis, worsening the patient´s prognosis. The objective of this study was to evaluate clinical and demographic aspects of patients with PVL and to compare them to patients diagnosed with OL. The diagnostic criteria reported on the literature were also revised. A retrospective study was performed and we analyzed patient´s records of Stomatology Department at FOUSP. Nine files of patients with PVL, diagnosed between 2007 and 2011 and 29 files of individuals with OL between 1997 and 2011 were studied. PVL showed higher incidence among women with no smoking or drinking habits with an average age of 73 years old while OL affected smoking and drinking patients, with a median age of 57 years old, with no gender predilection. PLV lesions progressed over a 5.4-year period while OL lesions took 19.3 months. Clinically, none of the PVL patients presented unifocal homogenous white lesion at the time of diagnosis. All of them showed aggressive and multifocal lesions, varying from homogenous to non homogenous aspect with verrucous surface and erythematous areas. OL individuals showed uni or multifocal white lesions with more restricted behavior. PVL group presented higher recurrence rate when compared to OL group. It is believed that not taking into account patients with multifocal lesions on the first visit can misdiagnose real PVL cases and waiting for the development of verrucous areas postpones the diagnosis and worsens the prognosis. It is suggested that PVL diagnostic criteria should include the presence of multifocal white lesions with aggressive behavior, long-term evolution, recurrences after any type of treatment and excludes the obligation of verrucous aspect on the time of diagnosis.