Biomedical subjects

Wai Hoe Ng

Publications and source records attributed to Wai Hoe Ng.

8 recordsLinked to original sources

PubMed2006

Disseminated spread of recurrent oligodendroglioma (WHO grade II).

Oligodendroglioma is a relatively uncommon primary brain tumour. The occurrence of metastatic dissemination of oligodendroglioma is rare and usually occurs in patients with anaplastic oligodendroglioma. The dissemination of WHO Grade II oligodendroglioma can occur and we report a patient with an initial diagnosis of a left temporal oligodendroglioma who presented with disseminated disease in the left temporal lobe, sellar region, medulla oblongata, both frontal lobes and ventricles more than 8 years later. Histology at dissemination showed anaplastic oligodendroglioma. Similar reports of metastatic dissemination of oligodendrogliomas reveal that the tumours may remain as WHO Grade II or may progress to anaplastic oligodendroglioma at metastasis. However, regardless of the histological grade at metastasis, the prognosis of metastatic oligodendroglioma is poor.

Humans↗

PubMed2005

Spinal and extracranial metastatic dissemination of malignant glioma.

Metastatic dissemination of malignant glioma is rare. Metastatic disease usually occurs within the neuraxis but extracranial spread to the liver, spleen, lung, peritoneum and lymph nodes can also occur. In most cases of metastatic disease, the patient has previously undergone a craniotomy. The prognosis is uniformly poor. The vast majority of patients do not survive beyond six months from diagnosis of metastatic spread of a primary intracranial tumour. The pathophysiology and natural history of this condition is still not fully understood, hence well-designed prospective studies are needed.

Brain Neoplasms↗

PubMed2005

Comparison of magnetic resonance spectroscopy and perfusion-weighted imaging in presurgical grading of oligodendroglial tumors.

OBJECTIVE: Oligodendroglial tumors form an uncommon, but distinct, subgroup of gliomas with longer survival, better treatment response, and characteristic genetic alterations. Noninvasive grading of oligodendroglial tumors using functional and metabolic magnetic resonance imaging may be helpful in guiding the treatment approach and predicting malignant transformation of these tumors. We used perfusion-weighted magnetic resonance imaging and proton magnetic resonance spectroscopic imaging (MRSI) to predict the oligodendroglioma grade. METHODS: Twenty-four patients with pathologically confirmed oligodendrogliomas underwent dynamic contrast-enhanced perfusion-weighted magnetic resonance imaging and/or proton MRSI before surgery. We assessed the ability of tumor contrast enhancement, normalized cerebral blood volume, normalized choline, and the presence of either lactate or lipid metabolites to correctly predict the World Health Organization tumor grade. The accuracy of tumor grading using each method was also compared. RESULTS: Tumor contrast enhancement (P = 0.069) and normalized cerebral blood volume (P = 0.181) were not significantly different between low and high-grade oligodendrogliomas. The MRSI measurement of normalized choline was significantly higher in high-grade (2.82 +/- 0.64) than in low-grade (1.62 +/- 0.46) oligodendrogliomas (P < 0.001), and the presence of lactate or lipid metabolites also correctly predicted high-grade tumors (P = 0.014). The maximum accuracy of contrast enhancement, normalized cerebral blood volume, normalized choline, and lactate or lipid metabolites in grading oligodendroglioma was 71, 83, 90, and 85%, respectively. CONCLUSION: MRSI measurements are more accurate than perfusion-weighted magnetic resonance imaging or conventional contrast enhancement in differentiating oligodendroglial tumor grade. In these inherently vascular tumors, metabolic measurements of mitosis and necrosis may be better than measures of neovascularity in presurgical grading.

Adolescent↗

PubMed2004

A case of hyperdense diploic epidermoid cyst on CT scan mimicking meningioma.

Epidermoid cysts typically have images characteristic similar to cerebrospinal fluid (CSF). A case of a hyperdense epidermoid cyst on computed tomography (CT) scan mimicking meningioma is described and the possibility of unusual imaging characteristics of epidermoids is highlighted as a diagnostic problem.

Adult↗

PubMed2003

Coexistence of aneurysmal subarachnoid haemorrhage and pituitary apoplexy: Case report and review of the literature.

A case of aneurysmal subarachnoid haemorrhage with associated haemorrhagic infarction of a growth hormone secreting pituitary macroadenoma is presented. The subarachnoid haemorrhage was not identifiable on CT, but was apparent on MRI. Angiography revealed a 7mm right posterior communicating aneurysm, a 3mm left A1 segment anterior cerebral aneurysm, and vasospasm. Surgery was performed through a right pterional/subfrontal approach, clipping both aneurysms and debulking the tumour. The left A1 aneurysm was the site of subarachnoid haemorrhage. There was evidence of haemorrhagic infarction of the pituitary tumour. Although rupture of an aneurysm into a pituitary tumour has been previously reported, this is the first case reported of aneurysmal subarachnoid haemorrhage with coexisting pituitary apoplexy where the aneurysm had not bled directly into the pituitary tumour. The literature regarding the association between pituitary tumours and aneurysm is reviewed.

Enzymes↗

PubMed2003

Lymphocytic hypophysitis.

Lymphocytic hypophysitis is a rare but important cause of pituitary hypofunction which predominantly affects young women in the peripartum period. It is believed to be an autoimmune disorder with an association with other autoimmune disorders and expression of anti-pituitary cytosolic and anti-nuclear antibodies. Clinically, it presents most frequently with symptoms and signs attributable to pituitary hypofunction, headache, visual disturbance and amenorrhoea. It is difficult to distinguish lymphocytic hypophysitis from a pituitary adenoma on pre-operative imaging and definitive diagnosis rests on histology which classically demonstrates destruction of anterior pituitary acini by an inflammatory infiltrate rich in plasma cells and T lymphocytes. Surgical management therefore plays a crucial role to obtain a histological diagnosis and to relieve pressure effects on the optic apparatus in patients with visual disturbances.

Adult↗

PubMed2002

Spinal epidural haematoma: MRI-aided diagnosis.

Spinal epidural haematoma is a rare cause of spinal cord compression. It is most commonly attributed to trauma and coagulation disorders. We report a case of a 64 year-old man with thrombocytopaenia who presented with a traumatic epidural haematoma who p resented with right hemiparesis which progressed to complete tetraplegia. MR of the cervical spine showed an epidural collection on the posterior aspect of the cord throughout the cervical spine. The patient underwent C1-C7 laminectomy and decompression. Postoperatively, the patient has improved gradually and has power of grade 3 (Medical Research Council classification of power) in all 4 limbs at 2-month follow-up. MRI is an important modality in the early diagnosis of spinal epidural haematomas and can facilitate emergent decompressive surgery which offers the best chance of neurological improvement.

Decompression, Surgical↗

PubMed2002

Lymphocytic hypophysitis mimicking pituitary macroadenoma.

Lymphocytic hypophysitis is an uncommon disease with a variable presentation and unclear pathophysiology. We present the case of a 30 year old woman who presented with features typical of a pituitary macroadenoma. She underwent a transphenoidal resection of the mass and histopathological examination revealed lymphocytic hypophysitis. This case illustrates the difficulty in differentiating pituitary macroadenoma and lymphocytic hypophysitis and the variable presentations of lymphocytic hypophysitis.

Adenoma↗