Intramedullary neurenteric cyst in mid thoracic spine in an adult: a case report.

Neurenteric cysts are very rare, particularly in adults. These are congenital intraspinal cysts of endodermal origin. A 67 years old man, presenting with backache and paraesthesiae of one and half years' duration, followed by subacute flaccid paraplegia, developing in a week is described. MRI revealed intramedullary cyst at T7. He underwent emergency thoracic laminectomy and complete excision of the cyst. Histopathology confirmed a neurenteric cyst. In view of their rarity, peculiarity in terms of age, location and presentation, we report this case.

Pituitary tuberculoma--a case report.

Pituitary tuberculomas, mimicking adenomas are very unusual. We describe a rare case of a patient with an exclusively intrasellar mass, and who presented with severe headaches and loss of libido. The lesion was approached trans-sphenoidally and pathological examination revealed a tuberculoma. Complete removal was achieved and the patient followed on anti-tuberculous therapy.

Ultrastructural changes in medullomyoblastoma. Similarities with foetal rhabdomyoma.

The light and electronmicroscopic changes are described in two cases of medullomyoblastoma, and compared with the changes seen in a case of foetal rhabdomyoma. The medullomyoblastomas in two children aged 8 and 5 years, consisted predominantly of classical type of medulloblastoma cells, along with few to many 'strap cells' or 'myoid cells' which, on closer examination, showed clear cross striations, consistent with muscle fibres or myofibrils. The primitive myoid cells were similar to those encountered in larger numbers in a post-auricular rhabdomyoma, possibly of foetal origin in a 40 day old infant. The four pathogenetic mechanisms i.e. (i) an embryonal stage of myofibrillar differentiation; (ii) a malformative factor; (iii) a teratoid factor on account of the presence of mesenchyme derived striated muscle tissue in the obviously predominant ectodermal medulloblastoma; and (iv) metaplasia of the vascular smooth muscle cells in the medullomyoblastoma, are discussed.

Isolated cysticercal infestation of extraocular muscles: CT and MR findings.

PURPOSE: We sought to document the appearance of isolated cysticercal infestation of single extraocular muscles on MR and CT studies, and to compare these findings with results of histopathologic examination. METHODS: Six MR and three CT examinations of the orbits of six patients were reviewed. Histopathologic confirmation of the diagnosis was available in three patients, and response to specific medical therapy was available in one. In all, the imaging findings were considered highly suggestive of cysticercal infestation. RESULTS: Typically, the affected extraocular muscle showed fusiform enlargement of its belly and contained a well-defined, spherical cyst with a nodule attached to its wall. The mural nodule was identified in all six cases with varying degrees of visibility. It was best seen on the CT examinations and in all cases in which contrast material had been administered. The nodule and the enlarged muscle showed intense enhancement on the contrast-enhanced studies. Imaging studies of the brain showed no evidence of cerebral cysticerci in any of the patients. CONCLUSION: The MR and CT appearance of isolated infestation of single extraocular muscles by the larva of the pork tapeworm Taenia solium is quite characteristic and often diagnostic of this condition.

Rabies: interactions between neurons and viruses. A review of the history of Negri inclusion bodies.

The first clear-cut description of a virus-nerve cell interaction was made by Adelchi Negri in 1903 with the detection of cytoplasmic bodies (Negri bodies) in subsets of neurons in the brain from rabies-infected animals. A biographical sketch of Negri is given here; he was born in Perugia, Italy, in 1875 and died in Pavia in 1912. In 1900 Negri became assistant to Camillo Golgi, who encouraged him to study rabies-infected brains with histological techniques. The report of intraneuronal bodies described by Negri as specific for rabies stimulated an intense debate both concerning their diagnostic value and their nature. The diagnostic value was finally determined in a study by Negri's wife, Lina Negri-Luzzani, in 1913, while the viral nature of the bodies had to await the introduction of electron microscopy and immunohistochemistry. However, the true significance of the Negri bodies is still mysterious, since they only develop in subsets of infected neurons and occur mainly after infection with wild, so-called 'street', virus strains and not after infection with strains passaged in the laboratory, so-called 'fixed' strains.

Pathology and pathogenetic mechanisms in neurotuberculosis.

The mechanisms and the changes described herein typically begin with a dense basal meningeal exudate often resulting from a "Rich focus" along the basal surface of the cerebrum or ventricular ependyma. In the interpeduncular fossa, when the exudate is copious, among other structures the proximal parts of the optic nerves and of the internal carotid arteries are seen surrounded and compressed by the exudate. This exudate is made up of small and large mononuclear cells, including epithelioid cells, which also act as macrophages and may fuse to form Langhans' giant cells. Further extension of this exudate along small proliferating blood vessels into the brain substance constitutes a border zone encephalitis with the development of focal and diffuse ischemic brain changes due to vasculitis. Entrapment and occasional arteritic occlusion of larger arteries, such as the middle cerebral in the Sylvian fissures, results in infarction. Blockage of the basal subarachnoid cisterns around the midbrain and pons by the dense basal exudate or narrowing of aqueduct and third ventricle by a small tuberculoma causes consequent hydrocephalus. Development of many or one large focal granuloma (i.e., tuberculoma) occurs in the cerebrum, cerebellum, and/or brain stem. Similar pathogenetic mechanisms produce tuberculous spinal meningitis myeloradiculopathy that may be secondary to or occur before cranial tuberculous meningitis. More extensive damage to the white matter may occur together with the infrequent onset of perivascular demyelination on the basis of a hypersensitivity reaction to tuberculoprotein (i.e., "allergic tuberculous encephalopathy"). Finally, there may be a part played by NO in the production of the vascular and perivascular inflammatory central nervous system changes and a role for the the potential beneficial action of corticosteroids, especially in cases of tuberculous encephalopathy.

Histopathology and fine structure of the brain in six cases of Creutzfeldt-Jakob disease from western India.

Light and electronmicroscopic changes in 5 formalin-fixed brains, and one glutaraldehyde-fixed brain biopsy, from patients with Creutzfeldt-Jakob disease in the age range of 45 to 65 years, are described. These 6 patients (out of 7 reported clinically earlier and 2 unreported) had classical manifestations with progressive dementia, pyramidal signs and myoclonic jerks. Light microscopy showed neuronal and nerve fibre loss, moderate or severe spongiform change, astrocytic proliferation and absence of inflammatory reaction. Electronmicroscopy confirmed the characteristic membranous profiles of the 'cysts' and 'daughter cysts' constituting the spongiform change. The membranes were generally dark and thin, either concentrically arranged or splitting and with stray pale broad segments. The one glutaraldehyde-fixed brain biopsy specimen showed cisterns of RER in close proximity to these 'cysts', suggesting the source of proteinous material of these membranes. Though mainly in the neurones and dendrites of the cortex, at times they were seen in the myelinated fibres also, a few of which showed dystrophic axons bearing dense bodies. One of the 6 patients had cerebellar signs also, and a total duration of the neurological illness of 36 months, as against 2-8 months in the 5 other patients. The histopathological examination of her brain revealed less spongiform change, and many cerebral cortical glial whorls, the centre of which showed PAS-positive and congo-red-positive material representing amyloid. Fine structural examination confirmed the glial whorls, and the filamentous nature of amyloid in the plaques, which resembled Kuru plaques. All brains also showed more or less intraneuronal lipofuscin.

The lung in tropical eosinophilia compared to that in pulmonary hypertension. Fine structural basis of respiratory disability.

Light and electronmicroscopic changes in lung biopsies were studied in six patients with tropical pulmonary eosinophilia, aged 20 to 37 years, of varying duration, and with severe haematologic (blood eosinophil count of 3,600 to 18,200 per mm3), and respiratory changes. On light microscopy the main pathologic reaction consisted of large mononuclear cells and eosinophils in and around the alveoli and blood vessels, and proliferated reticulin. Fine structural changes probably being described for the first time, included the presence of many alveolar macrophages characterised by abundant cytoplasm, irregular or stunted microvilli, increased phagolysosomes with ingested debris, and depletion of other organelles. Eosinophils bearing typical old and young granules, were encountered in and around the alveoli and blood vessels in all case, and collagenosis around alveolar cells in a few. Subacute pneumonitis producing compression and disorganisation of alveoli and blood vessels, and lack of normal apposition of air and blood spaces, appear responsible for the respiratory disability. The detection of mycobacteria, cocci or chlamydia-like bodies in two specimens and of intranuclear virus-like particles in another, could either indicate secondary infection or have an immunogenic significance, in the absence of detection of filarial elements in any of the specimens. Lung biopsies from two additional patients (aged 13 & 32) who had mitral stenosis probably due to rheumatic heart disease, and secondary pulmonary hypertension, were studied as "control" specimens. Both at light and electronmicroscopy these specimens did not show any eosinophils or neutrophils, and fewer macrophages in the lung parenchyma. In contrast to tropical eosinophilia and, as expected, there was considerably more fibrosis of the lung parenchyma, especially in the alveolar subepithelial region and in the vessel walls. This, together with fibroblasts full of endoplasmic cisterns, noted particularly in the younger patient with shorter duration, probably represented an earlier change in this condition.

Neuropathology & pathogenesis of experimental fenfluramine toxicity in young rodents.

The anorectic compound fenfluramine hydrochloride was injected into young Holtzman strain rats (from days 6 to 40 of life), at the dose of 75 mg/kg body weight. Intralysosomal lamellar bodies (LBs) were seen in the endothelial cells, pericytes, the perivascular astrocyte processes and occasionally in the lumen. The pathology of myelinated fibres varied from thinning of myelin to complete demyelination and, at times, presence of dense bodies in the axons, the changes perhaps being a result of the oligodendroglia damage. A small group of adult mice was administered three oral doses each of Ponderax equivalent to 5 mg of fenfluramine. The brain stem and cerebellar neurons of these mice showed abnormal dark cytoplasm, without lamellar bodies. Even in this short-term experiment, there was formation of a few LBs in the neuropil, the prominence of dark glial cells, probably oligodendroglia, and some perivascular intracytoplasmic oedema. The earliest detection of dense bodies in the undistended astrocyte processes before they were observed in the cell perikarya, both in the younger rats and the adult mice, suggested the perivascular astrocyte to be the first CNS constituent to come in contact with the toxic agent as it passes the blood-brain barrier. On the basis of our observations, it also appears that the 'myelinosomes' or lamellar phagolysosomes developing due to failure of degradation of drug-phospholipid interaction product, accumulate in different cells of the CNS.

Light and electronmicroscopy of the bowel in an unusual form of Hirschsprung's disease.

In a histological and histochemical study of multiple biopsies of unaffected segments of the bowel from 15 patients with Hirschsprung's Disease (H.D.), the AChE or non-specific esterase and the NADPH tetrazolium reductase enzyme reactions proved to be useful in identification of myenteric plexus islands; and acid phosphatase for the delineation of individual neurones. In the affected segment (usually aganglionic), this myenteric plexus tissue was not reactive for esterase, but individual nerve fibres among muscle fibres of the two muscle coats showed the enzyme product in a third of the cases. Fine structural study of biopsies from a typical case of H.D., showed normal looking axons and Schwann cytoplasm with terminals bearing both andrenergic and cholinergic vesicles in the unaffected colon, smooth muscle fibres with normal fine structure in all parts of the bowel, and loss of neurons with myenteric plexus replaced by nerve fibre groups in the affected rectosigmoid. One patient clinically presenting as a case of severe H.D., with histologically and histochemically normal myenteric and submucous ganglion cells, and not responding to resection of the bowel, showed degeneration of the unmyelinated axons with prominent Schwann cytoplasm, depleted cholinergic but persistent adrenergic vesicles, and markedly thinned and degenerating smooth muscle fibres and myofilaments, suggesting either a primary disorder of muscle tissue of the colon or, less likely, a denervation atrophy with secondary degeneration of the smooth muscle fibres.

Brain tumours in childhood in Bombay: I: Histopathology showing changing patterns; II: Tissue culture with light and electronmicroscopy, stressing ingestion & degradation of bacteria by glial cells in vitro.

The pathological pattern of 86 brain 'tumours' in childhood during the years 1981-85 (out of a total of 586 for all ages), showed a higher proportion of neoplasms and a much lower of tuberculomas compared to the preceding three decades. A large number of histologically unusual cases was revealed. Through tissue culture of brain tumours we carried out morphological, histochemical and fine structural study of the tumour cells in vitro. The abundant presence of lysosomal acid phosphatase, in outgrowing cells, correlated with the detection of lysosomal dense bodies and vacuoles in araldite sections, by light and electronmicroscopy. In view of the phagocytic propensity of schwann cells for M. leprae as the important factor in leprous neuritis, TC preparations of gliomas, (in addition to acoustic schwannomas and meningiomas), were inoculated with two mycobacteria, M. scrofulaceum and the ICRC bacillus. There was a pronounced intracytoplasmic uptake, i.e. endocytosis, of acid-fast bacilli by the growing cells of these tumours. This was confirmed by electronmicroscopy which showed intact and degrading bacilli in various stages, in such cells of a typical cerebral astrocytoma used as an illustrative case in this paper. Ingestion and Digestion appear to be an inherent property of growing tumour cells in vitro. Fine structural examination of in vitro growth of an unusual subependymal giant cell astrocytoma, not inoculated with bacilli, served as a control. Cells of both tumours showed copious autophagic activity and cytoskeletal features of developing microtubules and filaments.

Fine structure of A: autonomic nerve fibers and terminals in human myocardium; and B: myocardial changes in congenital heart disease.

In a histological and fine structural study of right atrial biopsy specimens from 31 patients with rheumatic heart disease (RHD), aged 7 to 46 years, and 11 patients with congenital heart disease (CHD), aged 3 to 36 years, nerve fibers or endings were seen by electron microscopy in 11 specimens. There was concurrence of ordinary axons along with terminals bearing pale cholinergic or dark adrenergic synaptic vesicles. Smaller and denser cholinergic vesicles suggested proliferation followed by exhaustion of such nerve endings. The closest proximity of nerve terminal to muscle fiber was about 100 nm. In one RHD specimen a "specific terminal cell" was present between a nerve ending and muscle fiber; in another a possible neuromuscular contact was developing at the surface of a regenerating small muscle fiber with a few myofilaments. Unmyelinated axons amidst increased subendocardial and subepicardial collagen, with prominent fibroblasts and depleted muscle fibers, were seen more frequently in specimens of CHD. Loss of myofibrils and accumulation of mitochondria, with infrequent formation of lipofuscin bodies, characterized degenerating muscle fibers in CHD also, although to a lesser degree than in RHD (reported earlier, 1985). The myocardial blood vessels in CHD tended to have pale swollen endothelial cells and narrowed lumen. The most severely affected cases of CHD were those with (1) a very wide atrial septal defect (ASD), (2) ventricular septal defect (VSD) with vegetations near the defect, (3) infundibular pulmonary stenosis, and (4) Fallot's tetralogy.

Pleomorphism of fine structure of rabies virus in human and experimental brain.

Identification of the Negri bodies in the brain of an 8-year-old boy who died 8 days after a paralytic illness and 20 days after a dog bite, and who had received 9 injections of Semple's anti-rabies vaccine, provided evidence that he died of acute rabies encephalitis and not of post-vaccinal allergic encephalomyelitis. The Negri bodies in the human subject and those seen in the inoculated mouse differed in their morphological structure: the former consisted of a matrix of very fine granular material bearing larger granules or strands of higher electron-density resembling nucleic acids and representing products of host cell-virus interaction; and the latter showed better defined areas of granular matrix containing tubular, bullet-shaped and elongated forms of viral structures, and nucleocapsids or capsule-deficient cores, representing the virions, emerging from them. Fine structural examination of the patient's brain and of the inoculated mouse has provided evidence of the pleomorphism of the Negri bodies and the various stages of formation of viral material and virions in them, the animal alone showing the mature virions of rabies, and proving the infectivity of the Negri bodies of the human brain.

Changes in atrial biopsies in chronic rheumatic heart disease. I: Cellulo-vascular and mesenchymal reaction.

The cellular, vascular and connective tissue changes were studied in 32 atrial biopsy specimens from patients with chronic rheumatic heart disease (RHD). 15 of these 32 specimens showed some inflammatory reaction, 7 with small mononuclear cells only and 8 with macrophage reaction amidst increased but necrotic collagen, especially in the subepicardial and subendocardial regions. Most cellulonecrotic foci were histologically consistent with a stage of Aschoff nodule. Acid phosphatase activity in frozen sections was seen in the cytoplasm of the macrophages. Fine structural examination showed membrane-bound vacuoles and lipofuscin bodies rather than ingested material in the macrophages. By light and electronmicroscopy, these macrophages were not different from those encountered in other granulomatous or necrotic conditions. There was moderate proliferation of blood vessels, with prominence of endothelial cells and pinocytotic vesicles, or fibrosis of media, or proliferation of basal laminae. The presence of Aschoff nodules in the right atrium, the least affected chamber in RHD, suggests a diffuse and smouldering pathology on the basis of a persistent subclinical cell-mediated immune (CMI) reaction.

Changes in atrial biopsies in chronic rheumatic heart disease. II: Muscle fibre reaction.

Myocardial fibres were studied in the right atrial biopsies from 32 patients with chronic rheumatic heart disease (RHD). Paraffin and, particularly, araldite sections showed many muscle fibres well preserved, and others with large hyperchromatic nuclei, or with depleted myofibrils and increased mitochondria. With the SDH and ATPase reactions, there was no type difference in the myocardial fibres, and the former showed the reaction predominantly in the centre while the latter showed it mainly at the periphery of the fibres. At electronmicroscopy, fibres with intact myofibrils were found close to "degenerating" fibres with variable degrees of myofibrillar and myofilament disorganisation and loss, mitochondrial proliferation, occasionally with degeneration of cristae, and accumulation of lipofuscin in varying amounts, and irregularly tortuous or loosened intercellular junctions. This study has revealed more severe muscle changes than expected, even in the clinically less affected right atrial chamber in chronic RHD. It is speculated that this might be due to subclinical involvement of the tricuspid valve, known to be frequent in Indian patients, and the resulting "back pressure" on the right atrium might lead to changes in its myofibres.