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Biomedical subjects

B Pasquier

Publications and source records attributed to B Pasquier.

At least 19 recordsLinked to original sources
PubMed1992

Brain-tissue cysts in rats infected with the RH strain of Toxoplasma gondii.

Virulent strains of the coccidian parasite Toxoplasma gondii become attenuated so as to survive and complete their life cycle; however, it is not known whether the attenuation process is attributable to an innate cystogenic capacity of the parasite or to host-induced mechanisms. This report presents direct evidence of RH cystogenesis in non-immunised Fischer rats and subsequent attenuation of RH pathogenicity in non-immunised mice following a single passage through rats. Taken together, these preliminary observations tend to suggest that at least one mechanism of T. gondii involves intermediate host attenuation.

Animals↗
PubMed1992

Central neurocytomas. Critical evaluation of a small-cell neuronal tumor.

We report herein the clinical and pathological features of 20 patients with central neurocytomas. Investigations for various differentiation antigens and cell type-specific markers were performed by immunohistochemistry using paraffin-embedded tissue. In addition, the expression of L1 adhesion molecule and of the various N.CAM (neural cell adhesion molecule) isoforms were investigated by immunoblotting studies in two frozen specimens. Central neurocytomas are clinically characterized by their intraventricular localization, occurrence in young adults, and good prognosis. It rarely occurs in patients over 50, but such cases have a poor prognosis. Total surgical excision is the best treatment. Radiotherapy is appropriate if surgery is incomplete or contraindicated. Histologically, central neurocytomas display the following features: an oligo-like pattern, usually associated with large fibrillary rosettes or perivascular arrangement, and a rich endocrine-type vasculature. Central neurocytomas have a remarkably homogeneous antigenic profile. GFAP expression is only found in scattered reactive astrocytes, S100 protein in reactive astrocytes and rare tumor cells. Among the pan-neuroendocrine markers, central neurocytomas always express neuron-specific enolase; they frequently express synaptophysin but never chromogranin A. Synaptophysin is the most reliable immunohistological marker for central neurocytomas; however, immunoreactivity could be lost with long formalin fixation. In these cases, electron microscopy is used to support the neuronal nature of the tumor cells. The expression of L1 adhesion molecule and the isoform 180 of N.CAM, indicates that central neurocytomas are formed by cells committed to neuronal phenotype. Nevertheless, advanced neuronal differentiation may be absent, as suggested by the persistence of embryonic N.CAM, the nonexpression of neurofilament proteins, and the absence of mature synapses in numerous cases. Central neurocytomas and neuroblastomas share some biochemical properties, but their respective clinicopathological features and biological behavior are dramatically different.

Adolescent↗
PubMed1992

[Tibial hyperostosis and Propionibacterium acnes].

In a 39-year-old patient with tibial productive osteitis, Propionibacterium acnes was identified in a surgical specimen of the bone lesion. Similar cases have been reported by others. The possibility that P. acnes may play in a pathogenic role in the SAPHO syndrome by causing inflammatory or infectious changes is discussed.

Adult↗
PubMed1992

[Spinal leptomeningeal tumor spread disclosing a pineocytoma].

A 39-year-old female was admitted to the hospital because of a sudden meningeal syndrome followed by diplopia, cervical, dorsal and sciatic nerve pains, and right peripheral facial palsy. Cerebrospinal fluid obtained by lumbar puncture showed a protein level at 23 g/l. Myelography and magnetic resonance imaging (MRI) were in favor of a lumbar arachnoiditis. A meningeal biopsy revealed a tumour infiltration with foci of cells that were stained with anti-glial fibrillary acidic protein antibody. Cerebral MRI was performed to search for a central nervous system (CNS) primary tumour, and disclosed a pineal mass. Five months after the onset of the disease, the patient worsened her clinical state and died. Necropsy confirmed the presence of a pineocytoma with astrocytic differentiation and diffuse leptomeningeal spread. This exceptional occurrence leads us to discuss about primary tumours of the CNS with leptomeningeal spread.

Adult↗
PubMed1991

Thymolipoma in association with myasthenia gravis.

A 52-year-old male presented with an anterior mediastinal tumor associated with a 2-year history of myasthenia gravis. The patient underwent thymectomy and a 185-g, 10 X 8 X 3.5 cm, well-delineated tumor was resected. On histologic examination the tumor proved to be a thymolipoma composed of mature adipose elements containing cords and nests of thymic tissue. The latter consisted mainly of cortical areas, the thymocytes of which displayed an immunohistochemical profile of cortical cells, i.e., CD 1+, CD 4+, CD 8+, and frequently Ki 67+. Ultrastructural study confirmed the predominant cortical differentiation of the thymic component. No germinal centers, dendritic reticulum cells, or myoid cells were detected by histologic, immunohistochemical, and ultrastructural studies. The association of thymolipoma with myasthenia gravis is rare; this case is the 10th reported. Our findings lead us to believe that (a) the cortical differentiation of the thymic component and the active thymocyte proliferation could represent a factor leading to myasthenia gravis; and (b) thymolipoma could be a peculiar form of thymoma rather than a mixed tumor of mesenchymal and entodermal origin, a lipoma, or a hamartoma of the thymic gland. The reported association of thymolipomas with other immune disturbances or with neoplastic conditions usually associated with true thymomas support these findings.

Antibodies, Monoclonal↗
PubMed1991

[Lipoma of the internal auditory canal. An anatomo-clinical case study and review of the literature about cranial nerve lipomas].

A 36-year-old female presented with vertigo and worsening of a right hearing loss with tinnitus. Clinical and radiologic investigations revealed a tumor of the right internal acoustic meatus, first diagnosed as a neuroma. Histologic study of surgical samples led to a final diagnosis of lipoma. Cranial nerve lipomas are rare and usually located in the cerebellopontine angle. Lipomas confined to the internal acoustic meatus are much rarer. The review of the literature however, shows that their histologic characteristics and their behavior are identical to those of cerebellopontine angle lipomas, and that a minimal surgical resection is therefore advised.

Adult↗
PubMed1991

[Brain stem tumors in children].

Gliomas involving the brain stem represent 10% of pediatric central nervous system neoplasms. They result in multiple cranial nerve involvement, long tracts signs, cerebellar signs, usually with no evidence of raising in intracranial pressure. The diagnosis is established by computed tomographic scan and magnetic resonance imaging. Classic management consists in conventional radiation therapy but the prognosis is very dismal with a five year survival rate about 30%.

Brain Neoplasms↗
PubMed1991

[Primary germinal tumors of the central nervous system].

Primary intra-cranial germ-cell tumors are a rare and heterogeneous group of neoplasms, identical to germ-cell tumors of gonads and other organs. These tumors arise along the midline, from the supra-sellar cistern to the pineal gland, and have neurological, ophthalmological, and endocrinological expression. The diagnosis is established by detection of increased levels of tumoral markers and/or by histological examination. The treatment includes chemotherapy, radiotherapy and surgery.

Brain Neoplasms↗
PubMed1990

[Villonodular synovitis. An uncommon localization: the ankle. Apropos of a case].

The authors report an uncommon soft tissue tumor, a diffuse giant cell tumor of tendon sheath. The location is uncommon too, the ankle, behind tibial shaft and forward achilleus tendon. The primary diagnosis of ankle and leg lymphoedema, has been for a long time. But CT Scan and MRI allowing the discovery of a firm and multinodular mass, have permitted surgical excision and histological diagnosis. This case agrees with the literature review. The pigmented villonodular synovitis is rather uncommon in comparison to localized form. Young people and lower extremities are more affected; symptoms are of relatively long duration. Histological examination gives diagnosis but surgical excision has to remove the tumor completely as possible because of local recurrence rate of about 50%.

Adult↗
PubMed1990

Apparently primary malignant melanoma of the cerebellopontine angle. One case.

We report a case of primary malignant melanoma of the cerebellopontine angle. This tumour showed RMI features that were totally different from those reported for secondary melanomas, and therefore its nature could not be suspected before surgery. Intracranial primary melanomas are so rare that no other published case is available for comparison, and our tentative explanations for the atypical RMI signals cannot be supported by evidence from the literature.

Cerebellar Neoplasms↗
PubMed1989

[Association of thymus carcinoma, Hashimoto's thyroiditis and polymyositis. Anatomoclinical case with autopsy findings].

A 67-year-old woman presenting with a 9-month history of polymyositis, suddenly worsened her clinical state and died. An autopsy was performed, finding a tumor measuring 8 x 6 x 1 cm, located in the left pulmonary hilum. The thyroid gland, of normal volume, was firm. The histological analysis of the tumor, the thyroid gland and several skeletal muscles led to the following diagnoses: thymic carcinoma, Hashimoto's thyroiditis and polymyositis. The aim of the discussion is this thymic carcinoma, the originality of which are firstly its ectopic location, secondly its association with immune diseases usually described during the course of thymomas rather than thymic carcinomas.

Aged↗
PubMed1989

Osteoid osteoma of the spine: radiological aspects and value of arteriography. Four cases.

The authors present four cases of osteoid osteoma of the spine and review the usual clinical and paraclinical data leading to its diagnosis. The value of radionuclide bone scanning is emphasized: it supersedes the often disappointing radio-tomography and guides computerized tomography which, with modern scanners, virtually always demonstrates the lesion and locates it with accuracy. In the author's experience, spinal and spinal cord arteriography plays an important role: it identifies the radiculospinal vessels preoperatively and provides additional aetiological arguments based on the usual hypervascularity of osteoid osteomas and on the pain induced by injection of the feeding vessels. Data from the literature concerning the vascularization of the nidus suggest that treatment by embolization alone can be envisaged but must be demonstrated.

Adolescent↗
PubMed1989

Spinal metastases of carotid paraganglioma. One case and review of the literature.

Paragangliomas of the carotid body are uncommon tumours usually regarded as benign or locally malignant. Metastasis occurs in 5 to 25% of the cases, involving mainly the liver, lung and bones. A case of carotid body tumour without histological evidence of malignancy but with local invasion and, subsequently, multiple spinal metastases is reported. Since the histological prognosis of the initial tumour is impossible to make in most cases, the authors underline the importance of signs of local invasion which is predictive of metastasis and requires regular monitoring with radionuclide bone scanning and MRI.

Adult↗