Biomedical subjects

W F Ng

Publications and source records attributed to W F Ng.

At least 55 records · Page 3Linked to original sources

PubMed1996

Paraffinomas of the breast: an oriental curiosity.

BACKGROUND: The injection of liquid paraffin wax was a form of breast augmentation practised in Hong Kong 30-40 years ago. Patients may present many years later with complications of this treatment. METHODS: The records of 43 patients diagnosed with paraffinomas of the breast at a teaching hospital in Hong Kong were reviewed. These patients had received paraffin injections 3-41 years (median 17) previously. RESULTS: Patients presented with hard masses in the breast 4-18 cm (median 17) diameter. Ulceration or infection occurred in 10 patients. Mammography revealed a honeycomb appearance in the affected breast. Treatment included biopsy only (7), excision of masses (3) and total mastectomy (30, bilateral in 27). Histology demonstrated hyalinized and densely sclerotic fibrous tissue with cystic spaces of various sizes. CONCLUSIONS: Awareness of this condition facilitates the differentiation from tuberculosis and carcinoma of the breast which often present late in this population of patients. Adequate treatment usually require total mastectomy.

Adult↗

PubMed1996

Single-tube nested PCR in the diagnosis of tuberculosis.

AIMS: To evaluate the usefulness of a single-tube nested polymerase chain reaction (PCR) assay in the diagnosis of tuberculosis in 1497 pulmonary and 536 extrapulmonary specimens. METHODS: A single-tube nested PCR, utilising two sets of primers with different melting temperatures (88 degrees C for external primers; 70 degrees C for internal primers) to augment sensitivity and specificity without increasing the risk of amplicon contamination, was evaluated. Specimens were initially tested for the repetitive IS6110 sequences and if negative, retested for the universal 38 kilodalton sequence and for inhibitors. dUTP/Uracil-N-glycosylase and Instagene treatment were used to minimise contamination and the effect of inhibitors, respectively. RESULTS: Using culture as the gold standard, the overall sensitivity of the assay was 89% for pulmonary and 42% for extrapulmonary specimens. Sensitivity varied greatly with respect to sample type (92% for follow up specimens from a chest hospital and 70% for non-follow up specimens from a general hospital). The smear positivity rates were 15% for extrapulmonary specimens, and 69% and 45%, respectively, for follow up and non-follow up specimens from pulmonary sites. Specificity was 99.7%. Inhibitors were present more frequently in extrapulmonary than in pulmonary specimens (13.4% v 2.7%). CONCLUSION: Despite the high sensitivity of the PCR assay for the diagnosis of tuberculosis in pulmonary specimens, it was less effective in the extrapulmonary samples. This is probably because of the lower bacterial load in extrapulmonary specimens, the presence of more inhibitors adversely affecting the PCR assay and the higher volume of specimens used for culture.

Base Sequence↗

PubMed1996

Mixed low grade and high grade endometrial stromal sarcoma of uterus: differences on immunohistochemistry and chromosome in situ hybridisation.

A case of a 64 year old woman with a tumour of the uterus is reported. The patient presented with postmenopausal bleeding and subsequently underwent total hysterectomy and bilateral salpingo-oophorectomy. Sections of the tumour showed a low grade endometrial stromal sarcoma coexisting with areas consistent with high grade sarcoma. The sarcoma cells, in both the low and high grade areas, were positive for vimentin and negative for desmin and cytokeratin on immunohistochemistry. While the sarcoma cells in the low grade region showed immunoreactivity for oestrogen and progestogen receptors, those in the high grade region did not. Using chromosome in situ hybridisation, the low grade portion of the sarcoma was diploid for chromosomes X, 11, 12, and 17, whereas the more anaplastic areas were aneuploid for these chromosomes. This case may represent an example of high grade endometrial stromal sarcoma arising by dedifferentiation from a low grade stromal sarcoma. Adequate sampling is important in identifying such anaplastic changes as the origin of the tumour will affect patient management.

Chromosome Aberrations↗

PubMed1995

Tension pneumocephalus--a rare complication of radiotherapy in nasopharyngeal carcinoma.

A patient with nasopharyngeal carcinoma (NPC) treated by radiotherapy developed tension pneumocephalus due to a naso-cranial fistula. The fistula was due to a pathological fracture at the base of skull affected by bone necrosis. The clinical features, neuro-radiological and post-mortem findings are presented. This is the first case report of pneumocephalus in association with NPC. The brain showed florid subarachnoid and intraventricular air collection under tension, low grade meningitis, foreign body giant cell reaction in the arachnoid membrane and multifocal cerebral infarction. Late radiation necrosis was also found in the left temporal lobe. The cause of the tension pneumocephalus in relation to radiation bone necrosis and the possible role of pneumocephalus in producing the multifocal cerebral infarction are discussed. The more common radiation necrosis of brain is also discussed. The pathogenesis of the pneumocephalus in this patient is distinctly different from the more common causes such as head injury and surgery.

Aged↗

PubMed1995

The expression of cathepsin D, oestrogen receptor and progestogen receptor in hydatidiform mole--an immunohistochemical study.

The expression of oestrogen and progestogen receptors, as well as Cathepsin D, an oestrogen-induced protease, in trophoblastic cells of 12 cases of complete hydatidiform mole, 12 cases of partial mole and nine cases of spontaneous abortions, were studied in an attempt to elucidate their possible roles in the pathogenesis of the diseases. The immunohistochemical studies were performed on formalin-fixed paraffin-embedded tissue using the ABC immunoperoxidase method. The intensity of staining and proportion of cells stained were assessed and compared in the three categories of lesions. Immunoreactivity for Cathepsin D was noted in both the syncytio- and cytotrophoblastic cells in all three lesions. Statistical analysis showed consistently stronger and more extensive staining for Cathepsin Din complete moles when compared with abortions. Staining for oestrogen and progestogen receptors was found to be weak in the tissues studied. The strong expression of Cathepsin D in trophoblastic cells of all three lesions, especially in complete mole, suggests that it might be important in the control of trophoblastic cell activities and involved in the pathogenesis of hydatidiform mole. The associated weak expression of sex hormone receptors also suggests that the expression of Cathepsin D in trophoblastic cells may be controlled by modes of regulation other than sex hormones.

Cathepsin D↗

PubMed1995

Neonatal haemochromatosis associated with Down syndrome.

METHODOLOGY: The clinical course of a child with neonatal haemochromatosis associated with Down syndrome is described, using case notes and post-mortem examination. RESULTS: The patient died of liver failure on day 36. Post-mortem examination showed siderosis of liver, pancreas, heart, kidney and thyroid. CONCLUSIONS: Neonatal haemochromatosis is a rare paediatric disease, the aetiology of which is unknown. Evidence suggests a disorder of fetoplacental iron handling with implications for recurrence in future pregnancies.

Down Syndrome↗

PubMed1995

Elevated serum alpha-fetoprotein in a patient with undifferentiated carcinoma of the gall bladder.

An uncommon case of undifferentiated carcinoma of the gall bladder in a 65 year old Chinese man, who presented with an increased serum alpha-fetoprotein concentration, is reported. Histologically, the tumour had a primitive appearance and was composed of a pavement-like array of poorly differentiated columnar/polygonal cells. Alpha-fetoprotein was demonstrated in some of the tumour cells using an immunoperoxidase technique. Alpha-fetoprotein secretion in this instance may have occurred because the gall bladder and the liver are of similar embryological origin. Alpha-fetoprotein may also be related to the resurgent expression of oncofetal antigens. This tumour may represent another rare cause of increased serum alpha-fetoprotein concentrations.

Aged↗

PubMed1995

Giant fibroadenomas of the breast in an oriental community.

Twenty-six patients were diagnosed to have giant fibroadenomas of the breast over a 19-year period. The majority of these tumours occurred in adolescents and young adults and the bimodal age incidence described in caucasians was not seen. Tumour sizes ranged from 5 cm to 11 cm. None of the patients presented with a clinical picture simulating malignancy of the breast. All tumours were treated by simple enucleation; no recurrences were observed over a minimum follow-up period of three years.

Adolescent↗

PubMed1994

Colonic hyperganglionosis presenting as neonatal enterocolitis and multiple strictures.

Neuronal intestinal dysplasia (NID) usually mimics Hirschsprung's disease, but rarely presents as neonatal enterocolitis. The authors report a case of colonic hyperganglionosis, which is a form of NID, presenting with postenterocolitis intestinal strictures. NID should be considered as a possible (although rare) cause of neonatal enterocolitis and may present with intestinal strictures.

Colon↗

PubMed1994

Miliary tuberculosis with splenic rupture: a fatal case with hemophagocytic syndrome and possible association with long standing sarcoidosis.

A fatal case of miliary tuberculosis complicated by splenic rupture and reactive hemophagocytic syndrome is presented. A 42 yr old Indian patient with a 7 yr history of sarcoidosis developed miliary tuberculosis and hemophagocytic syndrome after steroid therapy. A ruptured enlarged spleen with hemoperitoneum was detected at autopsy. This case highlights the need to consider the occurrence of tuberculosis in patients with sarcoidosis, especially after steroid therapy. Yellow bodies (Hamazaki-Wesenberg bodies), commonly but not exclusively found in sarcoidosis, were identified within the retroperitoneal lymph nodes in this case.

Adult↗

PubMed1993

Localized polyarteritis nodosa of breast--report of two cases and a review of the literature.

Two patients with localized polyarteritis nodosa involving the breast are reported. They presented with tender breast masses which were excised because of suspicion of carcinoma. The pathological features were similar with vasculitis of medium-sized and small arteries. The medium-sized arteries showed intimal fibroplasia, fragmentation of internal elastic lamina and inflammatory cellular infiltration. Fibrinoid vasculitis involving small arteries indicated a diagnosis of polyarteritis nodosa rather than giant cell arteritis. Both patients remain well. The differential diagnosis of these two arteritides and of Wegener's granulomatosis involving the breast is reviewed.

Aged↗

PubMed1993

Fatal necrotizing fasciitis due to Vibrio damsela.

A patient who succumbed to fulminant necrotizing fasciitis due to Vibrio damsela after injury by a rabbitfish is described. Despite the absence of any known underlying illness, he did not respond to appropriate antibiotic therapy and radical surgical intervention. This represents the first documented case of necrotizing fasciitis due to this organism, and is also the first reported case in Southeast Asia inflicted by rabbitfish.

Animals↗

PubMed1993

Cutaneous cryptococcosis--primary versus secondary disease. Report of two cases with review of literature.

The clinical, immunological, and pathological features of solitary cutaneous cryptococcosis in two apparently healthy Chinese adults are reported. In patient 1, regional cryptococcal lymphadenopathy also occurred. Both patients showed lymphopenia with a proportionate decrease in T-helper and T-suppressor cells. Both skin and lymph node biopsies showed granulomatous inflammation and the presence of cryptococcus. A chancriform syndrome developed in patient 1, indicating primary cutaneous cryptococcosis. Chancriform syndrome is rare in cryptococcal skin infection, probably due to immunosuppression in susceptible patients. In patient 2, the deep dermal and subcutaneous inflammatory involvement and anatomic location of the lesion on the upper medial thigh are supportive of secondary skin disease. Unless negated by a reliable history, the following features are indicative of secondary disease: inflammation centered in deep dermis or subcutaneous fat, lesion on covered parts of body, and multifocal skin lesions. Some cases remain unclassifiable. In practice the distinction between primary and secondary cutaneous cryptococcal disease is not essential because less toxic, effective antifungal drugs are now available.

Adipose Tissue↗

PubMed1992

Pathological basis of surgery in the management of postradiotherapy cervical metastasis in nasopharyngeal carcinoma.

Radical neck dissection was performed on 43 patients with nasopharyngeal carcinoma in whom persistent or recurrent cervical metastasis developed after radiotherapy. The pathologic nature of the tumor in the cervical lymph nodes was studied with step serial sectioning of the entire radical neck dissection specimen at 3-mm intervals. In 70% of patients, more tumor-harboring lymph nodes were detected in the specimen when compared with clinical examination. The extensive behavior of the tumor in the cervical metastases was reflected by the presence of extracapsular spread in 70% of the lymph nodes and the existence of isolated clusters of tumor cells in 35% of the specimens studied. Tumor tissue lying in close proximity to the spinal accessory nerve was demonstrated in 27.5% of the specimens, and 72% of the tumor-bearing lymph nodes were located in the posterior triangle. Radical neck dissection is recommended as the salvage procedure for these patients.

Adult↗

PubMed1992

Acute carpal tunnel syndrome caused by pseudogout.

Acute carpal tunnel syndrome caused by pseudogout occurred in a Chinese patient. The radiological findings mimicked those of synovial chondromatosis. Such radiological findings were very unusual. Diagnosis of such conditions may be difficult, since the clinical features may be confused with those of gout and infection. Surgical release is the treatment of choice.

Acute Disease↗

PubMed1991

Diffuse aortitis complicating Behçet's disease leading to severe aortic regurgitation.

Cardiovascular complications are uncommon in Behçet's disease, but are frequently the cause of morbidity and mortality. Venous and peripheral arterial involvement have been well documented, but involvement of the proximal aorta has rarely been described. This report details a Chinese patient with Behçet's disease. Diffuse aortitis led to proximal aortic dilatation and severe aortic regurgitation necessitating aortic valve replacement. Histopathology of the aorta revealed features similar to those observed in other systemic diseases with aortic involvement.

Adult↗

PubMed1991

An autopsy study of pulmonary thromboembolism in Hong Kong Chinese.

A retrospective study of autopsied material in the last 15 yrs is documented an increasing incidence of pulmonary thromboembolism (PTE) in Hong Kong Chinese. The incidence of significant PTE increased from 0.58% in the first 5 yr period to 2.08% in recent years. The topographic features and characteristics of these PTE patients are analysed and the factors contributing to the changes are discussed.

Adolescent↗

PubMed1990

Helicobacter pylori and associated duodenal ulcer.

Twenty three children with coexistent duodenal ulcer and Helicobacter pylori infection were treated with either two weeks of amoxycillin (25 mg/kg/day) in addition to six weeks of cimetidine, or cimetidine alone. Endoscopy with antral and duodenal biopsies for urease test, microaerophilic culture, and histological studies were performed at entry, six weeks, 12 weeks, and at six months. Children with persistent H pylori infection at six weeks were given a further two weeks' course of amoxycillin. H pylori persisted in all children not receiving amoxycillin treatment but cleared in six of the 13 children (46%) treated with amoxycillin. With failure of H pylori clearance at six months, only two out of six (33%) ulcers had healed and 50% of patients had experienced ulcer recurrence. In contrast, when H pylori remained cleared all ulcers healed and no ulcer recurred. Persistent H pylori infection was associated with persistent gastritis and duodenitis despite endoscopic evidence of ulcer healing. Detection and eradication of H pylori deserves particular attention in the routine management of duodenal ulceration in children.

Adolescent↗