Neuroma multicístico do acústico - relato de caso estudado com TC e RM com gadolino-DTPA / Multicistic acoustic neuroma: CT and MRI with gadolinium-DTPA evaluation

Os autores apresentam um caso raro de neuroma multicístico do nervo acústico estudado por tomografia computadorizada (TC) e ressonância magnética (RM), utilizando injeçäo endovenosa de constraste paramagnético (Gd-DTPA). Discutem os principais diagnósticos diferenciais e tecem consideraçöes sobre a técnica de exame

Sex hormone receptors in acoustic neuromas.

We performed quantitative assays for estrogen, progesterone, and testosterone receptors in 19 acoustic neuroma specimens from ten men and nine women. No patient received preoperative or intraoperative glucocorticoids, mineralocorticoids, or sex hormones. All tumors were unilateral and removed by the translabyrinthine approach. No tumor specimen was positive for estrogen or testosterone receptors. Three of ten men and seven of nine women had tumors positive for progesterone receptors (10 fmol/mg cytosol protein or greater). This between-sex difference was of borderline significance by the Mann-Whitney U test (p = 0.08). This finding indicates the need for further investigations of endocrinologic therapy as a possible treatment of acoustic neuromas.

Estrogen and progesterone receptors in acoustic neuromas.

Acoustic neuromas are more frequent, larger, and more vascular in women, and their growth rate increases during pregnancy. Estrogen receptors were claimed to be demonstrated in these neoplasms for the first time in 1981. Since then, numerous diverging studies, using various biochemical and histochemical methods, have been published on the contents of estrogen and progesterone receptors in acoustic neuromas. We determined the content of estrogen and progesterone receptors by means of an immunohistochemical method, using monoclonal antibodies, which has proved to be reliable, reasonably sensitive, and clinically relevant in other tissues, especially in breast carcinomas. No estrogen or progesterone receptors could be found in 18 consecutive acoustic neuromas from 7 men and 11 women, ranging in age from 26 to 73 years. The results do not support preoperative hormone treatment of acoustic neuromas.

Calmodulin content in human central nervous system tumors.

Benign and malignant brain tumors and normal cerebral cortex were assayed for calmodulin content by enzymatic and radioimmunoassay techniques. Normal cerebral cortex contained more (8.31 +/- 1.27 vs 3.30 +/- 0.42 micrograms/mg protein) calmodulin than the brain tumors. The contents of calmodulin in the malignant glioblastomas were significantly higher than the meningiomas (5.41 +/- 0.31 vs 2.97 +/- 0.16 micrograms/mg protein). These differences were independent of tumor location and persisted when calmodulin content was normalized for DNA rather than protein content. This data supports differences in the tissue calmodulin contents with normal cortex greater than primary malignant tumors greater than benign tumors greater than metastatic tumor tissue.

Sex hormone receptors in intracranial tumours and normal brain.

Fifty-four intracranial neoplasms (29 meningiomas, 16 gliomas, seven acoustic neuromas and two cerebral metastases) and nine specimens of normal brain were evaluated for specific progesterone and oestrogen receptor proteins using a dextran-coated charcoal assay and Scatchard plot analysis. Sixteen meningiomas (55%) were progesterone receptor (PgR) positive (median 52; mean 120; range 10-486 fmol mg-1 cytosol protein), whilst all were oestrogen receptor negative (ER-). Two (28%) of the acoustic neuromas contained small amounts of PgR protein, but all seven were ER-. None of the gliomas, cerebral metastases or specimens of normal brain contained ER or PgR protein. Analysis of PgR status and clinicopathological data suggest that there is no predictive correlation between PgR status and the patients age, sex, reproductive status, tumour histology or tumour behaviour. These results again suggest that in meningiomas PgR proteins are not modulated by oestrogens acting through ER. This finding may explain the failure of antioestrogen therapy to influence the growth of meningiomas. The significance of PgR protein in intracranial meningiomas is discussed with respect to tumour heterogeneity and implications for research with gene probes.

Estrogen and progestin receptors in acoustic and spinal neurilemmomas. Clinicopathologic correlations.

Estradiol and progestin receptors were studied in 20 patients with neuraxial Schwann cell tumors, and their presence was correlated to the clinicopathologic features and the amount of preoperative corticosteroid therapy. Based on an arbitrary cutoff value of 200 fmol per gram of tumor as indicative of a positive receptor value in breast cancer, 4 and 13 of the neurilemmoma tissue samples could be considered as positive for estrogen and progesterone receptors, respectively. Whereas there was no convincing correlation between the estrogen and progestin receptor activity and the age, sex, or menopausal status of the patients, overweight patients had significantly higher estrogen and progestin binding values. The correlation between the amount of preoperative prednisone therapy and the amount of [3H]estradiol and [3H]promegestone binding revealed no dose relationship. Correlating [3H]estradiol and [3H]promegestone content with the histologic type of the schwannomas (Antoni types A and B, respectively), we were not able to draw conclusions, because of the predominance of Antoni type A over Antoni type B tissues in our material. The necessity of nuclear receptor assays, ligand specificity testing, and in vitro studies is stressed as a prerequisite for answering the questions whether neurilemmomas contain genuine sexual steroid hormone receptors and whether these receptors are regulated via an estrogen-estrogen-receptor system as is the case in classical sexual steroid hormone target tissues.

[Specific receptors for sex hormones in tumors of the central nervous system]. / Receptores especificos de hormonas sexuales en tumores del sistema nervioso central.

The hormone sensitivity of some tumors seems to be mediated by the presence of specific receptor proteins, and a correlation seems to exist between the amount of receptor molecules and the behavior of the tumor evolution. Epidemiological data suggest a relation between the steroid sexual hormones and the development of some tumors of the central nervous system (CNS). The authors determine the amount of receptors specific to 17-beta-estradiol and progesterone in several cases of meningioma, glioma, neurinoma and intracerebral metastases. 17-beta-estradiol receptors were always detected, although in very variable amount (3 to 74 fm/mg protein). Progesterone receptors were found in all the studied CNS in women, and only in a few male gliomas, in amounts varying between 3 and 17 fm/mg protein. The significance of hormone receptors in the CNS tumors need further studies to know if they can be applied to prognosis and suggest the assay of a complementary endocrine therapy of CNS tumors.

Implications of DNA characterization of human acoustic neuromas.

Based on in vitro detection of cell-mediated immunity against human acoustic neuroma extract, a malignant potential of acoustic neuromas could be surmised, as malignant DNA patterns have been demonstrated in benign pituitary tumours. Flow-cytofluorometric characterization of the DNA content in 10 human acoustic neuromas, however, only revealed diploid cell lines and normal distributions of cells in different cell cycle phases. All acoustic neuromas were histopathology benign. The percentage of cells in S-phase (range: 1.8-8.3%, median: 3.6%) reflected a slow growth rate correlated neither to age, size of tumour, nor length of case history at time of surgery. These findings may in part be due to the analytical variation in the determinations of the S-phases. The investigation has not offered any explanation for the observed cell-mediated immunity against acoustic neuromas, and confirms that acoustic neuromas are benign tuours.

Electrophoretic separation and identification of perilymph proteins in cases of acoustic neuroma.

Previous studies of perilymph proteins have emphasised the difficulty of obtaining samples free of blood or serum proteins. The present investigation has established a method of polyacrylamide gel electrophoresis, which enables contaminated specimens to be readily identified and therefore discarded. Analysis of uncontaminated samples has confirmed the presence of an elevated perilymph protein in cases of acoustic neurinomata. Perilymph proteins have been separated and identified and although no characteristic pattern of proteins associated with acoustic neurinomata has emerged, further work should be undertaken to establish the site of origin of perilymph proteins and the pattern of abnormalities to be expected in pathological processes.

Cerebrospinal fluid and acoustic neurinoma specific proteins in perilymph.

White rabbits were immunized with pooled and concentrated cerebro-spinal fluid (CSF) and with tumour homogenate concentrate from specimens taken from five patients with acoustic neurinoma. The absorbed anti-CSF-antitumour antiserum was tested with the micro-immunodiffusion test against normal human serum (NHS), CSF, perilymph and CSF from tumour patients and tumour homogenate. NHS showed no precipitates in any of the tests. One protein band was observed in all the other four reactants. Tumour tissue and perilymph had two proteins in common. Diffusion from the CSF space into the perilymph can thus occur via both the cochlear aqueduct and the internal acoustic meatus.

S-100 protein in soft-tissue tumors derived from Schwann cells and melanocytes.

In soft tissues outside the central nervous system, S-100 protein is found normally only in Schwann cells. Using the peroxidase-antiperoxidase immunohistochemical method S-100 was also found in tumors derived from Schwann cells and melanocytes, including neurofibromas, neurilemomas, granular cell myoblastomas, cutaneous nevi, and malignant melanomas. S-100 was not detected in malignant Schwannomas, neuroblastomas, oat cell carcinomas, medullary carcinomas of the thyroid, paragangliomas, or meningiomas. S-100 was also absent from neoplasms of soft tissues not usually considered to arise from cells of neural crest origin. S-100 appears to be a useful marker for identifying neoplasms derived from Schwann cells and melanocytes.

Quantitated determination of proteins in perilymph in patients with acoustic neuromas.

Perilymph, cerebrospinal fluid (CSF) and plasma from 19 patients with acoustic neuromas were examined for albumin, alpha 2-macroglobulin and IgG. Patients with otosclerosis were used as controls. A highly significant increase of the tested proteins was found in perilymph from patients with acoustic neuromas. Determination of the tau-transferrin, which is a specific CNS protein, could neither be demonstrated in plasma nor in perilymph. This is in favour of the assumption that perilymph is plasma-derived and not concentrated CSF. Various causes for the high protein concentrations are discussed, and it is suggested that the increase is caused by a blockage of the neuroaxonal transport mechanisms.

Human acoustic neurinomas: nervous system specific biochemical parameters.

A series of 24 human acoustic neurinomas from 24 patients has been assayed for several biochemical parameters characteristic of the nervous system. S 100 protein, 2', 3'-cyclic nucleotide 3'-phosphohydrolase activity, and the myelin lipids galactosylceramide and sulfogalactosylceramide (sulfatide). Myelin basic protein was not detected. These finding further support the neuroectodermal origin of the human acoustic neurinoma, and provide additional biochemical markers for further study.