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In rare instances, demyelinating disorders present with radiological features that mimic a brain tumour. This often leads to biopsy, which--apart from carrying significant morbidity--frequently turns out as nondiagnostic or dispensable. We therefore set out to assess the contribution of repeated conventional magnetic resonance imaging (MRI), 1H-MR spectroscopy and magnetization transfer imaging in establishing a correct diagnosis of tumefactive demyelinating lesions (TDLs). We studied two females and one male, who presented with TDLs that led to brain biopsy in two cases, for up to three years. TDLs were characterized by the following features: (a) delayed or absent response to high-dose steroids together with progressive lesion growth over several weeks; (b) late or sparse enhancement, ill-defined borders, signal inhomogeneity and considerable concomitant oedema; and (c) normalization of initial increases in lipid and lactate peaks within three to four weeks, followed by persistent, marked reductions of the neuronal marker NAA and MTR values around or below 30%. These imaging characteristics reflected the histological correlate of marked demyelination in the absence of significant inflammation. MRI techniques thus appear to have the potential to establish a correct diagnosis of this subtype of TDLs. Awareness of these possibilities might obviate the need for biopsy at least in some cases in future.

In oligodendroglial neoplasms, losses of chromosomal material at 1p and 19q associate with chemosensitivity and prolonged survival. Thus, 1p/19q testing is increasingly proposed for use in brain tumor diagnosis and prognostic assessment. Fluorescent in situ hybridization (FISH) is a classic technique for investigation of 1p/19q status in paraffin-embedded tissues. A major limitation of this method is truncation of tumor cell nuclei complicating assessment of hybridization results. In our study, we analyzed 1p and 19q status in a series of 79 oligodendroglial neoplasms (49 oligodendrogliomas, 30 oligoastrocytomas, WHO: 57 Grade II, 22 Grade III tumors) and controls (gliotic brain tissue: n = 4, diffuse low-grade astrocytoma: n = 4) using FISH on isolated whole tumor cell nuclei, prepared as cytospin preparations, thus bypassing the problem of nuclear truncation. For interpretation of FISH results, we used consensus criteria as defined by the SIOP-Europe Neuroblastoma Study Group for analysis of peripheral neuroblastic tumors. FISH yielded interpretable results in 98.7% for 1p and 92.1% for 19q. Chromosome 1p/19q alterations comprised deletions (1p: 79.5%, 19q: 80%) and imbalances (1p: 11.5%, 19q: 12.9%). 1p aberrations were more frequent in oligodendroglioma than in oligoastrocytoma (100% versus 75.9%, P =.001). The frequency of 1p/19q alterations was not significantly different in WHO Grade II or Grade III tumors or in primary and recurrent tumors. We conclude that FISH on isolated cell nuclei, with application of the SIOP Europe Neuroblastoma consensus criteria, is a sensitive method for detection and interpretation of 1p and 19q aberrations in paraffin-embedded tissue specimens of oligodendroglial neoplasms.

In a 42-year-old women a recurrent anaplastic ependymoma of the frontal lobe developed intracerebral metastases and, after implantation of an atrioventricular shunt, also metastasized to the lung, pleural cavity and mediastinal lymph nodes. In routinely stained smear preparations of the pleural effusion sediment, the typical cytologic features of an anaplastic ependymoma were found--papilliform cell clusters with acellular axes ("pseudorosettes"), incomplete true ependymal rosettes, and epithelioid and tanycytoid tumor cells with signs of anaplasia. A peculiar matrix material was a characteristic feature of this case and, to our knowledge, was not reported previously. It consisted of refringent, fibrillar strands composed of tightly packed, roundish to rodshaped granules. This matrix seemed to be associated with the cytoplasmic processes of the tumor cells.

In a 19-month-old patient with mucopolysaccharidosis I (Pfaundler-Hurler, MPS I/H) high-pressure hydrocephalus required the implantation of a ventriculo-peritoneal shunt. Despite a reduction in both ventricular volume and intracranial pressure, clinical symptoms suggesting compression of the brain stem persisted. Brain MRI revealed a tumor within the posterior cranial fossa. Cytologic examination of the cerebrospinal fluid was suggestive of a poorly differentiated ependymoma. High-pressure hydrocephalus is a common complication in MPS I/H. As changes in mucopolysaccharide metabolism may be associated with an increased risk of developing neoplasms, the possibility of an intracranial tumor should be considered in patients with MPS I/H and high-pressure hydrocephalus.

This paper presents the experimental and clinical results of interstitial 1.06 Nd:YAG laser thermotherapy (ILTT) for brain tumors under real-time monitoring by magnetic resonance imaging. The authors chose a laser heat source for interstitial thermotherapy of brain tumors for several important reasons: (1) Laser heat delivery is less complicated and more controlled; (2) laser effects on tissue can be tested, monitored, and controlled by MRI. A 1.064 nm Nd:YAG laser and a specially designed laser optic fiber (ILTT) were used in C.W. mode this study. The laser was used at 4 W at a C.W. mode pulse and total exposure duration was 10 minutes (total energy was 2400 joules). Temperature distribution was determined with a microprocessor-based thermometer and by the levels of the signal intensity under MRI. The relationship between the temperature and MRI signal intensity allowed exploration of the possibility of using MRI as a noninvasive temperature monitoring method. Two patients with glioblastoma and one patient with a brain metastasis were treated with this modality. The results and indications are presented and discussed.

Thirty-five selected intracranial tumors qualifying as primitive neuroectodermal tumors (PNETs) were investigated; these included medulloblastomas, cerebral neuroblastomas, pinealoblastomas, retinoblastomas, polar spongioblastomas, ependymoblastomas. For control purposes 11 tumors, including glioblastomas (small cell, spongioblastic variants), one anaplastic astrocytoma (astroblastic component), anaplastic oligo-astrocytomas, gangliogliomas, one primary melanoblastoma, and one pineal germinoma, were also studied. Six neuronal markers, i.e., synaptophysin, chromogranin A, neuron-specific enolase (NSE), neurofilament protein (NFP) (160 kDa, 200 kDa, 70 and 200 kDa), and six other markers (glial fibrillary acidic protein, S-100 protein, vimentin, myoglobin, desmin, cytokeratin) were investigated immunohistochemically. A certain recapitulation of the ontogenetic development of neuronal differentiation in PNETs is given by the fact that chromogranin A immunoreactivity can regularly be seen already in poorly differentiated neurons and synaptophysin in well-differentiated ones. Immunostaining for NFPs showed different results depending on the subunit investigated. NSE reaction gave different results even within the single tumor groups. This study is, to the best of our knowledge, the first attempt to evaluate and compare, by combined morphological and immunohistochemical methods, PNETs without and with different stages of cellular differentiation with the stepwise differentiation of the human embryonic neuroectoderm.

A 50-year-old female patient died of an untreatable glioma apoplecticum. At autopsy a strongly vascularized glial tumour was found. The criteria for malignancy according to the WHO classification were only partially fulfilled by this tumour which displayed morphological features of an astrocytoma but could not be further subclassified. By light microscopy, angioma-like vascular proliferations, large cells with brightly eosinophilic cytoplasm, and small cells with hyperchromatic nuclei were found. Most large cells had vesicular, excentrically placed nuclei and contained fibrillary whorls or amorphous, irregular cytoplasmic inclusions. By immunohistochemical staining, using antibodies to glial fibrillary acidic protein (GFAP) the fibrillary whorls were identified as aggregates of glial filaments. The amorphous inclusions lacked GFAP immunoreactivity and appeared in the electron microscope as electron dense material surrounded by a dense network of glial filaments. The abnormal perikaryal inclusions of these atypical astrocytoma cells appeared to be peculiar alterations of Rosenthal fibres closely mimicing Mallory bodies.

A case of 14-year-old girl is reported in whom an alveolar rhabdomyosarcoma occurred in the soft tissues of the left forearm 4 years prior to death. Despite extensive surgery as well as chemotherapy and radiotherapy the tumor recurred locally and produced extensive metastases including a metastasis to the brain. Cerebral metastases have not yet been reported in the literature despite extensive reports on the pathology of alveolar rhabdomyosarcoma. The morphological diagnosis of rhabdomyosarcoma was supported by the immunohistochemical demonstration of desmin, myosin, and myoglobin in the tumor cells.

Primary lymphomas are rare brain tumours. A case is reported where the true histiocytic origin was proved by autopsy. The CT features and the differential diagnoses in malignant lymphomas of the brain are discussed.

Clinical, radiological and morphological findings in the case of a 79-year-old patient with a primary malignant histiocytosis of the brain are reported. The tumor was exclusively situated in the brain as proven by autopsy and was spreading on the inside of the lateral ventricles. The demonstration of atypical histiocytic cells in the CSF and the immunohistochemical demonstration of lysozyme, alpha 1-antitrypsin and alpha 1-antichymotrypsin which are typical for histiocytes, underline the histiocytic origin of the tumor.

The International World Health Organisation (WHO) classification of central nervous system tumours does not give an extensive classification of germ cell tumours and other malformative tumours and tumour-like lesions. In the same way, no consistent classification of dysontogenetic brain tumours can be found in the classical handbooks. For an eventual new edition of the WHO classification, it is proposed to reconsider and improve the classification of these tumours, based on their ontogenetic relations.