Biopsy material from two cases of histologically proven malignant choroid plexus papilloma was studied by electron microscopy. Both tumours differed from benign papillomas in showing poorly differentiated areas with numerous mitoses. Even in such areas, however, a number of ultrastructural features characteristic of normal choroid plexus tissue were observed in both the cases, including cilia, microvilli, a continuous basement membrane and capillary endothelial fenestration. Such findings may be helpful in establishing the primary origin of malignant tumours in the choroid plexus, especially where light microscopy of poorly differentiated biopsy samples makes diagnosis uncertain.

Biopsy↗

PubMedDate not supplied

Observations on the nature of subependymoma: an electron microscopic study.

Surgical biopsy material from four cases of symptomatic fourth ventricle subependymoma, all with typical light microscopic features, was studied by electron microscopy. The ultrastructural appearance of each case was similar, with small groups of tumour cell perikarya widely separated by a meshwork of cell processes containing glial filaments. Large cells lacking specialised features were prominent in all cases and showed similarities with ependymoglial precursor cells described in the adult subependymal layer of animals. Other cells showed either astrocytic or poorly developed ependymal features, and transitional forms between these two appearances were common, suggesting the tumour to be of a single cell type. Pockets of microvilli were present, but they differed from ependymal-type microrosettes in lacking tight junctional complexes. Unlike low grade astrocytomas, the extracellular space was small and there was no close association of tumour cell processes with blood vessels. These observations suggest that the subependymoma may be regarded as a separate entity from other fourth ventricle neoplasms and possibly takes origin from ependymoglial cells normally present in the adult subependymal layer.

Aged↗

PubMedDate not supplied

Immunohistochemical characteristics of haemangiopericytic meningiomas: comparison with typical meningiomas, haemangioblastomas and haemangiopericytomas from extracranial sites.

The relationship between malignant vascular meningeal tumours and typical meningiomas remains controversial, despite the need for accurate diagnostic distinction between the two, and some forms of vascular meningioma may be more closely allied to haemangioblastomas or extracranial haemangiopericytomas than to true meningiomas. In order to try to clarify the diagnostic characteristics and origins of the entity known as haemangiopericytic meningioma, 10 histologically typical cases were stained by the immunoperoxidase technique with a panel of seven antibodies. The results were compared with those obtained from typical and angiomatous meningiomas, haemangioblastomas and haemangiopericytomas from extracranial sites. Both the haemangiopericytic meningiomas and the extracranial haemangiopericytomas showed a similar staining pattern, which differed from that of the typical and angiomatous meningiomas in the strikingly focal nature of the vimentin staining and the lack of reactivity with antibodies to epithelial elements. The haemangioblastomas were less consistent in their individual staining characteristics, but had a quite different overall pattern from all the other tumour types. It is, therefore, suggested that so-called haemangiopericytic meningiomas are in fact primary haemangiopericytomas of the meninges, antigenically distinct from true meningiomas and displaying a malignant potential appropriate to haemangiopericytomas arising in any other sites.

Antibodies, Monoclonal↗

PubMedDate not supplied

Atypical motor neuron disease with features of a multisystem degeneration: a non-familial case with prominent sensory involvement.

A 66-year-old male with no family history of neurological disease developed symmetrical paraesthesia, numbness and flaccid weakness of the hands and feet. Both the weakness and sensory loss became progressively more severe, and spread to involve the forearms and lower legs. Limb muscle wasting and tongue fasciculation only became apparent late in the disease course, and death eventually occurred from respiratory failure eight years after the onset of symptoms. Postmortem examination revealed most of the typical histological features of motor neuron disease, but in addition there was degeneration of the spinocerebellar tracts and spinal cord posterior columns, with degeneration and loss of their associated neuronal perikarya in Clarke's nuclei and dorsal root ganglia. The clinical and pathological features of this case suggest that it is a non-familial but atypical form of motor neuron disease, and support the concept that this disease represents part of a spectrum of neuronal degenerative processes rather than a circumscribed disorder limited to motor neurons.

Aged↗

PubMedDate not supplied

Clinical and autopsy findings in two cases of MELAS presenting with stroke-like episodes but without clinical myopathy.

We report the clinical and autopsy findings of two patients with mitochondrial myopathy, encephalopathy, lactic acidosis and stroke-like episodes (MELAS). The cases were unusual in that both patients presented with stroke-like episodes and neither patient had clinically evident myopathy, consequently in neither case was the correct diagnosis made during life. Despite the absence of myopathy clinically, at autopsy skeletal muscle showed the characteristic features of mitochondrial cytopathy. One of the patients, in addition to the features of MELAS, also had gastrointestinal involvement at presentation which was sufficiently severe to warrant surgery and a peripheral neuropathy.

Adolescent↗

PubMedDate not supplied

Progressive myoclonus epilepsy with focal brainstem degeneration and paternal inheritance. An autopsy report of 4 cases from 2 pedigrees.

Four autopsied cases of myoclonus, ataxia, and epilepsy from 2 separate pedigrees are described. An identical pattern of focal brainstem lesions was found in all the cases with selective and symmetrical degeneration of the dentate and second order somatosensory nuclei. The combined clinical and pathological features did not appear to match any familial disorder previously described as causing progressive myoclonus epilepsy. Myoclonus epilepsy with ragged red fibres was excluded on the grounds of paternal inheritance and negative muscle biopsy findings, but the more acute lesions seen in 1 case are reminiscent of those found in Leigh's syndrome, and suggest that some other form of inherited defect of oxidative metabolism may be involved.

Brain Stem↗