Adenomas hipofisarios : estudo clinico, morfologico e morfometrico; busca de fatores de prognostico utilizando o metodo imunoistoquimico / Pituitary adenomas : a clinical, morphological and morphometric study : searching for prognostic factors with the immunohistochemical method

AUTOR(ES)
DATA DE PUBLICAÇÃO

2007

RESUMO

Pituitary Adenomas (PA) are an easily identifiable and benign epithelial neoplasia. They are clinically detected through symptoms of an increased or decreased hormone rate and/or alterations of intra-cranial mass. They are classed in accordance with radiological / macroscopical aspects (macro versus microadenoma / invasive versus non-invasive), functional status (functional versus non-functional), cytological (acidophil, basophilic and chromophobic) and immunohistochemical / ultra-structural (somatotrophinomas, prolactinomas, corticotrophinomas, thyrotrophinomas, gonadotrophinomas and those from null cells). Amongst their various forms of disclosure, evolution, and clinical manifestation, invasive adenomas and non-invasive macroadenomas impose limits to surgical procedures, resulting in recidivist determination of endocrine and / or neurological morbidity. Aggressive and non-aggressive variants may display similar histological aspects, which require immunohistochemical, genetic and molecular-biological investigation, attempting to relate tumorigenesis mechanisms to the biological behavior of these tumors, such as invasive growth and recurrence. Objectives Classification and study of the occurrence of the sampled PA under a functional viewpoint based upon clinical symptomatology; Neuro-radiological / anatomic classification based upon tumor size and invasive rate through the Jules Hardy labeling index; Analysis and classification of the occurrence of hormonal subtypes, through the immunohistochemical method; Co-relate clinical, anatomical, and immunohistochemical data with the aggressivity of the PA, seeking prognostic factors using proliferous activity markers (Ki 67), suppressive tumorous gene alteration (p53 and menin), angiogenesis (CD 34) and neuropeptide (galanin). Materials and Methods 61 PA patients who had undergone surgical re-section were studied: clinical, anatomical / neurological, and immunohistochemical aspects were considered. The immunohistochemical technique was used to determine the different hormonal subtypes, and for the Ki 67 as a proliferation marker, the p53 and menin as a tumor suppression marker, CD34 for the assessment of the agiogenesis, and galanin to observe the presence of this neuropeptide. Results The sample contains 57 (93.4% macro-adenomas (19 invasive and 38 non-invasive) and 4 non-invasive microadenomas; the invasion rate equaled 62.3%. Twenty-five (41%) PA are clinically functional (13 somatotrophinomas, 6 prolactinomas, 6 corticotrophinomas) and 36 (59%) non-functional (32 PA silenced and 4 null cells). Invasive, non-functional macroadenomas stood out when compared to invasive, functional macroadenomas (p=0.014). 54.09% recidivists were detected. Immunohistochemistry revealed positive expression of the growth hormone (GH) in 18 PA, 10 PA expressed prolactin (PRL), 12 showed positive for corticotrophin (ACTH), 17 for gonadotrophin, and 4 PA showed negative for all hormones. Endocrine symptomatology occurred in 42.62% of the cases, and neurological symptoms were present in 88%. Male and female patients were affected indistinctly, and most PA patients were in their 40s and 50s. Ki 67 was positive in 83.69% of the total sampled, rating at an average of 4.39% (varying from 0 ? 36.9%); amongst hormonal subtypes, PA showing positive expression of GH (mono or plurihormonal) had a significantly increased proliferative activity when compared to other subtypes (p=0.001). Invasive, functional macroadenomas showed a higher proliferation rate than invasive, non-functional macroadenomas (p=0.0328). p53 was positive in 60.65% of the total sampled, and the average rate of dyed nuclei equaled 1.23% (varying from 0 ? 16%). There was no meaningful change in the expression of p53 as to the invasion, hormonal phenotype, functional and recidivist status. However, a positive co-relation between the proliferation rate and the p53 was detected (p=0.0004). Concerning the angiogenesis, CD34 showed that the microvascular density (MVD) in PA is lower when compared to the healthy adenohypophysial tissue. Galanin (GAL) was positive in 57% of the cases. The PA negative for GAL showed significantly increased MVD rates than the GAL positive (p=0.0464). Immunoreaction for menin was positive in 41 PA (67.21%) and negative in 20 PA (32.7%). The large variety of menin expression, regarding chromatic intensity and cytoplasmic or nuclear location made the interpretation of the results more difficult, which required comparative genetic studies that could guide the understanding of the data obtained. Conclusions Higher rates of non-functional PA cases may be a result of late diagnosis. Ki 67 expression could not be linked to the Hardy index. Invasive, functional macro-adenomas showed a higher proliferation rate than the rate obtained from the non-functional types ? which may signal increased aggressivity. Amongst the various PA subgroups, only those with GH positive expression had a significantly higher proliferation rate. The invasion of PA ?10 mm, whose proliferation rate was null, is not dependent on proliferative activity. In this sample, the largest p53 expression matched the highest proliferation rate (Ki 67). p53, MVD and GAL are not PA prognostic markers. The highest MVD rates among PA combined with a null GAL expression may indicate more aggressive biological behavior

ASSUNTO(S)

sindrome das neoplasias endocrinas multiplas tipo 1 genes p53 genes ki 67 galanin pituitary gland p53 multiple endocrine neoplasia type 1 cd 34 imunohistoquimica cd 34 antingen immunohistochemistry galanina ki 67 hipofise

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