Search

A 10-yr-old female lion (Panthera leo) presented for acute onset ataxia and weakness with a history of two seizure episodes 6 mo prior to presentation and a persistent head tilt for at least 6 mo. Gross necropsy findings included a gelatinous mass in the right cerebral hemisphere extending from the frontal to the occipital lobes. Histologically, the mass was composed of polygonal cells surrounding lakes of mucinous material. These cells had clear cytoplasm, ovoid basophilic nuclei, and inapparent cell processes. Immunoreactivity was positive for S100 and neuron-specific enolase but negative for glial fibrillary acid protein, myelin basic protein, neurofilament triplet, vimentin, and cytokeratin. All findings were consistent with an oligodendroglioma. A second neoplasm, a pulmonary adenoma, was also iidentified at necropsy.

Objective: To investigate immunoexpression of 2 cyclin-dependent kinase inhibitors, p18INK4C (p18) and p14ARF (p14), in oligodendrogliomas and to evaluate the possible association with tumor grade and clinical outcome., Design: One hundred seventeen specially selected cases of cerebral oligodendrogliomas were studied retrospectively. Tumor specimens were immunohistochemically examined with antibodies to p18INK4C (118.2) and p14ARF (FL-132) proteins. A computerized color image analyzer was used to count immunostained nuclei., Results: p18 nuclear immunoexpression was found in 57 (49%) of the oligodendrogliomas we studied. p18 immunoreactivity exhibited a clear tendency to elevate with increasing tumor grade, and the mean p18 labeling index was 9.7% for low-grade (World Health Organization [WHO] grade II) and 19.2% for high-grade (WHO III) tumors. p14-immunopositive nuclei were found in 87 (74%) tumors, and p14 immunoreactivity showed no correlation with oligodendroglioma histological malignancy. Survival times were significantly reduced for p18-positive tumors, and risk of death was independently associated with p18 expression (hazard ratio = 2.48; P =.01). There was no difference in survival times in patients with or without p14 immunoreactivity., Conclusions: p18 protein expression is closely associated with malignant oligodendrogliomas and worse clinical outcome. It seems unlikely that p14 immunohistochemistry will be of value in assessing individual prognosis for these tumors.

Two midline oligodendrogliomas in young males were successfully totally removed after preoperative irradiation. A 33-year-old male with right lower extremity weakness had a large hypervascular mass occupying the left lateral ventricle. Even after 31 Gy whole-brain irradiation, massive bleeding occurred at surgery and resulted in only partial removal. The residual tumor markedly regressed with disappearance of abnormal vascularity after subsequent local boost irradiation. At the second operation, the tumor was totally removed. A 32-year-old male with progressive headache had a hypervascular mass with gross calcification in the right lateral ventricle. The tumor was partially resected due to its abundant vascularity and blood loss. After 60 Gy local irradiation, the tumor was moderately shrunk with a significant reduction in vascularity. At the second operation, the tumor was totally removed. Preoperative irradiation as an adjunct to surgery may increase the resectability of highly vascular tumors such as midline oligodendrogliomas.

Two examples of intracerebral neurilemmoma occurred in the absence of von Recklinghausen's disease. The first case was unique because the patient was clinically asymptomatic, and the second case was unusual with a combination of oligodendroglioma and neurilemmoma in the same mass. The latter lesion arising in persons without stigmata of neurofibromatosis has not been described. The nature of nerve sheath neoplasms in both instances has been verified by electron-microscopy. Clinical features of this rare neoplasm differ from those of acoustic or other cranial nerve tumour, particularly in relation to age and sex. Intracerebral neurilemmoma has been found most often in the first two decades of life and more often in males. Seizures and paresis, although non-specific are common signs and symptoms. Probable histogenesis of this neoplasm from perivascular elements in brain has been suggested.

A transmission electron microscope study was made of eight childhood brain tumors divided up into three zones, center, edge, infiltrating zone, and also of adjacent "normal-looking" brain. In seven of eight tumors, the numbers of Weibel-Palade bodies in endothelial cells were significantly increased in peripheral zones compared with central zones. A similar significant increase was observed after treatment of chick chorioallantoic membranes with tumor angiogenesis factor. It is suggested that large numbers of Weibel-Palade bodies may be a marker for proliferating endothelial cells in vivo.

We have developed a model to study the neoplastic transformation of rat oligodendrocytes in culture. This procedure utilizes a technique previously developed by McCarthy and de Vellis which allows the preparation of 99% pure astrocyte and oligodendrocyte populations from 1- to 2-day-old rat cerebral cortices. Pregnant rats on the 19th day of gestation were given injections with either ethyl nitrosourea (10 micrograms/g body weight) in phosphate-buffered saline or phosphate-buffered saline, and oligodendrocyte cultures were prepared. Oligodendrocytes appear to be unstable in culture since transformation was observed with cells derived from either pups from pregnant rats either treated with nitrosourea or phosphate-buffered saline. Transformation required 78 to 108 days and 3 to 9 passages, at which time a marked increase in cellular proliferation was observed. The possibility that the transformed cells were derived from a nonoligodendroglial cell was excluded by the following evidence. Light and scanning electron micrographs of the transformed cells revealed cytological features essentially similar to those of primary oligodendroglial cultures. Furthermore, 2 biochemical oligodendroglial markers, the induction of lactate dehydrogenase by N6,O6-dibutyryl cyclic adenosine 3':5'-monophosphate and the presence of 2',3'-cyclic nucleotide 3' phosphohydrolase, were also retained. Conversely, another oligodendroglial marker, the hydrocortisone induction of glycerol phosphate dehydrogenase, was not found in any of the cell lines. These transformed cells grew as tumors when injected intracranially into 21-day-old rats. Histologically, these tumors did not appear as classical oligodendrogliomas, but their oligodendroglial origin was confirmed since the tumor tissue contained 2':3'-cyclic nucleotide 3'-phosphohydrolase activity, and the cells which grew from tumor explant cultures morphologically appeared similar to the parent cell line. The transformed cells were also characterized for in vitro properties which correlate with the expression of tumorigenicity. The transformed cells exhibited anchorage-independent growth and were agglutinated by concanavalin A treatment. Changes in fibrinolytic activity were not an exclusive property of transformed glial cells. This model should now allow us to study various mechanisms involved in the neoplastic transformation of oligodendrocytes.