Beta-catenin mutations in craniopharyngiomas and pituitary adenomas.

Craniopharyngiomas and pituitary adenomas are both tumors of the hypothalamic and pituitary region, respectively that are frequently associated with endocrine defects either because of direct involvement of hormone producing cells (most pituitary tumors) or because of secondary defects due to disturbance of hypothalamic function (some pituitary tumors and craniopharyngiomas). Some studies suggest that mutant beta-catenin gene cells in craniopharyngiomas and pituitary adenomas contribute to their tumorigenesis. DNA was extracted from 73 cranial tumors and subjected to polymerase chain reaction (PCR) with previously described primers encompassing glycogen synthase kinase-3beta phosphorylation sites of the beta-catenin gene. Sequenced PCR products for possible beta-catenin gene mutations showed a total of 7/43 alterations in adamantinomatous craniopharyngioma-derived DNA samples. Two previously described beta-catenin mutations in codon 33 TCT(Ser) > TGT(Cys) and codon 37 TCT(Ser) > TTT(Phe), whereas three novel mutations in codon 41 ACC(Thr) > ATC(Ile), codon 33 TCT(Ser) > TAT(Tyr) and codon 32 GAC(Asp) > AAC(Asn) were observed. None of the 22 pituitary adenomas and the eight papillary craniopharyngiomas analyzed presented any sequence alterations. These findings demonstrate an association between beta-catenin gene alterations and craniopharyngiomas of the adamantinomatous type. Since this gene product is involved with development, these results suggest that beta-catenin mutations may contribute to the initiation and subsequent growth of congenital craniopharyngiomas.

Nuevas consideraciones en el diagnóstico del queratoquiste odontogénico / New considerations about the diagnosis of odontogenic keratocyst

El queratoquiste odontogénico (QO) es una forma clínica e histológicamente bien diferenciada de otros quistes odontogénicos. Es conocido por su agresividad, elevada tasa de recurrencia y puede estar asociado al síndrome del carcinoma basocelular nevoide (SCBN). Recientemente se ha propuesto en la literatura que la pérdida del gen supresor de tumor patched humano (ptch) es el posible origen molecular del QO. En este trabajo se revisan las características clínicas, histopatológicas y moleculares de los QOs, discutiéndose también el tratamiento y la recurrencia (AU)

Cell proliferation markers in the odontogenic keratocyst: effect of inflammation / Proliferação de células marcadoras em queratocistos odontogênicos: efeito da inflamação

The immunohistochemical expression of PCNA and Ki-67 proteins and the histochemical expression of AgNORs were studied in 20 odontogenic keratocysts in order to assess the relationship between epithelial cell proliferation and inflammation within the capsule. Immunostained cells were quantified by conventional methods, and both quantitative and morphometric analyses of AgNORs were performed by TV image analysis. Non-inflamed odontogenic keratocysts showed a typical epithelial lining and inflamed odontogenic keratocysts were lined also by hyperplastic non-keratinized stratified squamous epithelium. A statistically significant increase of PCNA+ and ki-67+ cells and of AgNOR numbers was detected in the linings of inflamed odontogenic keratocysts compared to non-inflamed lesions. The results suggest the existence of greater proliferative activity in the epithelial cells of inflamed odontogenic keratocysts, which may be associated with the disruption of the typical structure of odontogenic keratocyst linings

Diagnóstico das lesões fibro-ósseas benignas da maxila e mandíbula / Diagnosis of benign fibro-osseous jaw lesions

As lesões fibro-ósseas benignas constituem um importante grupo de alterações patológicas da maxila e mandíbula. A diversidade de termos utilizados para denominar estas entidades dificulta o entendimento entre clínicos, radiologistas e patologistas. O propósito dos autores neste estudo é fazer uma revisão conceitual destas lesões, ressaltando os principais aspectos clínicos, radiográficos e histológicos da sua ocorrência no complexo maxilo-mandibular