Estudo clínico, radiográfico, microscópico e perfil imunoistoquímico dos ameloblastomas: a experiência do Hospital A. C. Camargo / Clinico radiographic, histologic and immunohistochemical study of ameloblastomas: the A. C. Camargo Hospital experience

RESUMO

Os Ameloblastomas são tumores odontogênicos que exibem crescimento lento, porém mostram-se localmente agressivos. Este estudo teve como objetivo avaliar e correlacionar os achados clínico-radiográficos, histopatológicos e a expressão imunoistoquímica de diversos marcadores em Ameloblastomas e estabelecer informações relevantes quanto biologia, tratamento e prognóstico deste tumor. ... Os dados foram analisados estatisticamente usando os testes estatísticos apropriados, dentre eles o método de Kaplan-Meyer e a regressão logística de Cox. ... A análise estatística univariada mostrou que o aspecto radiográfico multilocular, a presença de corticais ósseas rompidas e o aspecto histológico folicular indicaram maior chance de recorrência. ... Podemos concluir que o ameloblastoma mostrou distribuição semelhante entre os gêneros, predominância na quarta e quinta décadas de vida na região posterior de mandíbula. O padrão sólido foi o mais comum e radiograficamente estes casos exibiram predominantemente o padrão multilocular com aumento estatisticamente significativo na incidência de rescidivas quando comparado aos casos sólidos uniloculares. A presença de cortical mandibular perfurada também indicou um maior risco para a recorrência (6,5 vezes). O epitélio dos ameblastomas foi itensamente positivo para as citoqueratinas AE1AE3, 34β12, 14 e 19. O tempo de queixa com positividade para Syndecan-1 foi estatisticamente menor do que os casos negativos. Além disso, os ameloblastomas mostram imunopositividade para EGFr e PTHrP.

ABSTRACT

Ameloblastomas are benign odontogenic tumors that exhibit slow growth, but have shown to be locally aggressive. The aim of this study was to evaluate and correlate the clinical-radiographic, histopathologic findings and immunohistochemical expression of various markers in Ameloblastomas and establish relevant information regarding biology, treatment and prognosis of this tumor. This was a retrospective study of 121 cases of Ameloblastomas diagnosed and treated at the "Hospital A.C.Camargo" between 1953 and 2003. All cases were confirmed histologically, classified and a selection of areas for the Tissue Microarray were done. Antibodies were analyzed to investigate prognostic and cell proliferation factors, (anti Ki-67; p53, EGFR, Syndecan-1 (CD 138), PTHrP) and to investigate the tumoral histogenesis (vimentin and cytokeratins Ck 1, 4, 6, 7, 8, 10, 14, 16, 18, 19 and 34ß andAE1/AE3). The data ere statistically analyzed using the appropriate statistical tests, among them twhe Kaplaars) n-Meyer method and Cox logistic regression. Patients' ages ranged from 02 to 82 years (mean = 33.2 ye with slight predilection for females. The majority of cases affected the posterior region of the mandible (80%) Radiographically, 60% showed multilocular pattern. Solid Ameloblastomas accounted for 113 cases, and the plexiform histologic type was the commonest. Solid tumors were treated by resection in block, curettage associated with cryotherapy, or only curettage, and unicystic tumors only by conservative procedures. The global recurrence rate was 22.1% with a mean follow-up time of 9.7 years. Univariate statistical analysis showed that the radiographic multilocular aspect, presence of ruptured bone corticals and the follicular histologic aspect indicated greater chance of recurrence. Positivity for cytokeratins AE1/AE3, 34ß12, 14 and 19 and negativity for cytokeratins 1 and 10 strengthened their odontogenic profile. The innumerable histologic subtypes and great variability of cellular differentiation in each tumor makes some cytokeratins, such as CKs 6,7, 8, 16 and 18 and vimentin show focal and specific expressions. Syndecan-1 howed negativity for 18.2% and weak positivity for 42.1% weak positivity for it. In the evaluation for Ki67, the majority of the samples of the cases. It showed statistically significant association with the time of complaint, in other words, cases positive for this marker showed a shorter time of complaint than the cases in which Syndecan-1 was negative. EGFR was expressed in the majority of cases, irrespective of the histologic subtype, but showed no association with any clinical and radiographic parameter. PTHrP showed 100% positivity in our casuistic and statistical analysis showed that patients with strong positivity for this marker were at an older age than patients with presented marking between 0-25% of tumoral cells. The marker p53 showed positivity in 82.5% of the cases and of these, 40.7% with immunoreactivity between 51-100% of the tumoral cells. In conclusion, ameloblastoma showed similar gender distribuition, most of the cases occured in the fourth and fifth decades and the majority affected the posterior region of the mandible.The solid pattern was the most common and, radiographically those cases were predominantely multilocular. The multilocular pattern showed a statistically higher tendendy to recurrence when compared to the solid unilocular type. Moreover, a perforated osseous cortical increased 6.5X the chance for recurrence. Tipically, the Ameloblastoma epithelium was positive for citokeratins AE1AE3, 34ß12, 14 and 19. The time of complain for the positives cases of Syndecan-1 were statistically lower when compared to the negative cases and solid ameloblastomas were positive for EGFr and PTHrP.