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Biomedical subjects

T P Poon

Publications and source records attributed to T P Poon.

At least 19 recordsLinked to original sources
PubMed1996

Subacute sclerosing panencephalitis and acquired immunodeficiency syndrome: role of electroencephalography and magnetic resonance imaging.

Subacute sclerosing panencephalitis (SSPE) had largely disappeared from the United States because of nearly universal measles vaccination, but it has reemerged in children infected with human immunodeficiency virus (HIV). Two children with SSPE are described. The first was HIV positive and presented with seizures and encephalopathy at the age of 21 months. The second developed myoclonus and dementia at age 4 years; she was not infected with HIV, but her mother had acquired immunodeficiency syndrome. Magnetic resonance imaging findings were nonspecific and could have been compatible with HIV encephalopathy. Electroencephalography was characteristic of SSPE, showing high-voltage, periodic slow-wave complexes and background slowing. The diagnosis of SSPE was confirmed by brain biopsy or high measles antibody titers in the cerebrospinal fluid.

AIDS Dementia Complex↗
PubMed1994

Pineal toxoplasmosis mimicking pineal tumor in an AIDS patient.

A pineal mass in a patient with acquired immunodeficiency syndrome (AIDS) is reported. Computed tomography (CT) scan revealed a nodular mass in the pineal region with foci of calcification and obstruction of the aqueduct mimicking a pineal tumor. At autopsy, the brain revealed a well-circumscribed lesion with central necrosis in the pineal region suggestive of toxoplasma and involving the periaqueductal area. Susceptibility of a patient with AIDS to opportunistic infections should be considered.

AIDS-Related Opportunistic Infections↗
PubMed1993

Giant collagen plaques in Creutzfeld-Jakob disease. Report of two cases with ultrastructural studies.

We report two cases of Creutzfeld-Jakob disease with clusters of giant collagen fibers. To our knowledge, these abnormally large collagen fibers have never been described in patients with degenerative diseases of the central nervous system. The significance of the formation of such plaque-like large collagen fibers has as yet not been elucidated. It is felt that these represent a product of the degenerative process.

Adult↗
PubMed1993

Multiple spinal intradural schwannomas in the absence of von Recklinghausen's disease.

A case of multiple spinal schwannomas is reported without any evidence of other manifestations of neurofibromatosis. Although cases of multiple schwannomas have been described in the setting of "Schwannomatosis," this case is unique in that all tumors were within the spinal canal. The presence of a schwannoma should prompt a complete investigation for other tumors of the nervous system preferably with magnetic resonance imaging.

Adult↗
PubMed1990

Carcinoma of the cervix with extensive endometrial and myometrial involvement.

Verrucous carcinoma is a rare variant of epidermoid carcinoma with distinct clinical and histopathologic features. To date, 31 cases have been reported in the cervix. They are typically slow-growing, locally invasive tumors with low potential for lymphatic metastasis and appear to be radioresistant. We report a case which is unusual in having endometrial and deep myometrial invasion. Electron microscopy, immunohistochemical stains, and DNA in situ hybridization studies failed to detect human papilloma virus particles but the oncogenic potential of the virus is not excluded.

Aged↗
PubMed1989

Haemorrhage in cerebral toxoplasmosis. A report on a patient with the acquired immunodeficiency syndrome.

A patient with the acquired immunodeficiency syndrome (AIDS) presented to hospital with a haemorrhagic cerebral lesion. The lesion was biopsied and electron microscopy confirmed a diagnosis of toxoplasmosis. Although known in congenital cases, haemorrhagic infarction is unknown in adults suffering from cerebral toxoplasmosis. Severe vasculitis with subsequent thrombosis and extensive fibrinoid necrosis of the vessel wall or direct parasitism of endothelial cells with subsequent destruction and seepage of blood appear to be the possible mechanisms in a situation where the T-cell immune mechanism and tissue cell response are compromised. Other intracerebral haemorrhagic lesions in AIDS were reviewed.

Acquired Immunodeficiency Syndrome↗
PubMed1988

Third ventricular primary cerebral neuroblastoma. Electron-microscopic and immunohistochemical study.

A case of third ventricular primary cerebral neuroblastoma with secondary hydrocephalus is reported. Light microscopy showed a cell pattern that resembled either ependymoma or oligodendroglioma. The tumor was confirmed to be neuroblastoma by electron microscopy and immunohistochemistry. Immunoperoxidase staining was positive for neuron-specific enolase and negative for glial fibrillary acidic protein.

Adolescent↗
PubMed1985

Mixed teratoma and meningioma in the temporoparietal region.

A case of a teratoma mixed with meningioma in the left temporoparietal region in a patient with progressive memory impairment, bradyphasia, loss of visual acuity of the left eye, and left leg weakness is presented. Histological findings showed fibroadipose tissue containing gland-like structures and lymphocytoid cells alongside a meningothelial meningioma. It is unusual for a teratoma to occur in the temporoparietal region; even more unusual is its proximity to an unrelated tumor in the same location.

Brain Neoplasms↗
PubMed1980

Cerebral cysticercosis with aqueductal obstruction. Case report.

The authors report a case of cerebral cysticercosis which presented with generalized nonspecific neurological signs and symptoms attributed to acute aqueductal obstruction, with concomitant intracranial hypertension. These were characteristic intracranial calcifications along with angiographically demonstrated signs of hydrocephalus. Contrast encephalography clearly demonstrated aqueductal obstruction. Pathologically, the aqueductal obstruction was shown to be due to parasitic invasion of the brain stem with compression of the aqueduct. The presence of typical intracranial calcification in conjunction with either obstructive or normal-pressure hydrocephalus should alert the observer to the possibility of cerebral cysticercosis.

Acute Disease↗
PubMed1976

Chronic cerebellar stimulation in epilepsy. Clinical and anatomical studies.

Ten of 15 patients subjected to chronic cerebellar stimulation have had previously intractable seizures modified or inhibited up to periods of three years. Stimulation of anterior lobe appears to be more efficacious than stimulation of posterior lobe. Cerebellar biopsies, obtained in five patients at the time of stimulator placement, revealed in every instance a reduction in the molecular layer, decreased or absent Purkinje cells, and decreased stellate cells. One unimproved patient died during a seizure 17 months after stimulation was initiated. Histological examination of the brain did not reveal tissue damage attributable to the stimulator. There is no evidence of any adverse effect of chronic cerebellar stimulation in humans who have undergone stimulation for periods up to three years.

Adolescent↗
PubMed1975

Membranous glomerulopathy in a patient with sarcoidosis.

We describe a case of membranous nephropathy in a patient with pulmonary, splenic and hepatic sarcoidosis. The patient was asymptomatic, and edema was absent notwithstanding the proteinuria (over 8.0 gm/100 ml daily). Prednisone cleared the pulmonary and splenic complications, but the proteinuria, although diminished, persisted. Adjunctive therapy with cyclophosphamide caused further diminishment of the proteinuria. We have reviewed the relationship between the nephropathy and the sarcoidosis and suggest that a causal relationship exists between the two diseases.

Adult↗