Biomedical subjects
Publications and source records attributed to W M Tsang.
Human dirofilariasis is a helminthic zoonosis that is common in some parts of the world. A sporadic case of dirofilariasis affecting the buccal mucosa has been reported in a non-endemic area of southern China. Clinical findings, diagnosis, pathogenesis and management are discussed. This is the fourth case of human dirofilariasis involving the oral mucosa reported in world literature.
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Massive defects of the upper aerodigestive tract present a reconstructive challenge. We report a case in which a large defect of the naso-oropharyngeal and oesophagus was reconstructed with a combination of a gastric pull-up and a pectoralis major muscle flap. Postoperative function was good and survival was in excess of 16 months. The history of such reconstructions and possible alternative techniques are also discussed.
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The purpose of this paper is to study the efficacy of applying stereotactic navigation guidance to nasopharyngectomy via a minimally invasive transnasal approach as compared with the conventional open transfacial approaches. The nasopharynx is the centre of the anterior skull base, which is remote from the surface of the facial skeleton. It is well known that there are several surgical approaches for access to resect tumours from the nasopharynx. However, the open techniques have been associated with much morbidity and only provide access to, and identification of, the ipsilateral internal carotid artery that forms the lateral boundary and resection limit of the nasopharynx. The coupling of stereotactic navigation guidance and a minimally invasive transnasal approach for nasopharyngectomy allows the surgeon to identify and protect the internal carotid artery bilaterally at the nasopharynx. This technique reduces operating time and morbidity to a minimum and yet is oncologically sound for resecting nasopharyngeal lesions. We compare 15 patients who underwent the stereotactic navigation guidance approach with 20 patients who received a conventional open transfacial approach.
We describe the first reported case of tracheal necrosis following a thyroidectomy. This complication resulted in massive subcutaneous emphysema and pneumomediastinum, which required emergency exploration of the neck to decompress the trapped air. We also discuss the suggested etiology and management of this rare condition.
We describe the imaging features of a 53-year-old Chinese patient with Kimura's disease (KD) who presented with a dominant right-cheek subcutaneous mass. The lesion appeared as an ill-defined mass within the subcutaneous tissues with a "wooly" echotexture on US. The differential diagnosis and a review of the literature are discussed.
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Mucoepidermoid carcinoma is one of the most common of the salivary gland neoplasms. Histologically, it is classified as either a low-, intermediate-, or high-grade tumor, and there are significant differences in prognosis among the different grades. Patients with low-grade disease have an excellent chance of survival. High-grade tumors behave aggressively, and they frequently manifest as local recurrences and distant metastases. We describe a case of a high-grade mucoepidermoid carcinoma of the parotid gland that had metastasized to the skin, stomach, and liver. The disease culminated in a rapidly fatal bleeding from the stomach metastasis. Such a complication is unusual and to our knowledge has not been previously reported. We briefly discuss the clinical features, biologic behavior, and treatment of this tumor.
Cowden's disease is a hereditary disorder characterized by oropharyngeal fibrosis and multiple hamartomas with potential malignant changes. We treated a 47-year-old man who had fibrotic lesions on the left vocal fold and an extensive amount of papillomatous lesions on the mucosa of the lips, tongue, and pharyngeal wall and on the skin of the axillae and buttocks. The pattern of distribution and the histopathologic features of these mucocutaneous lesions were diagnostic of Cowden's disease. To the best of our knowledge, this is the first reported case of Cowden's disease involving a vocal fold.
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The cephalometric characteristics of skeletal anterior open bite (AOB) in a southern Chinese population were evaluated in a group of 104 subjects with AOB and were compared with a control group of 40 subjects without AOB. The anteroposterior jaw relationship in the AOB group was Class I in 43%, Class II in 14%, and Class III in 43%. Cephalometric analysis of all subjects was completed by using 24 skeletal and 12 dentoalveolar measurements. Sexually dimorphic variables were identified and compared separately between groups with independent t tests. Two levels of significance were used, P < or = 0.05 and P < or = 0.001. Sexual dimorphism of cephalometric variables was present in both the test and the control groups, but affected more variables in the test group. Significant findings in AOB were shorter anterior cranial base, upward and forward rotation of the maxilla, increased gonial and mandibular plane angles, increased upper posterior dental height, and increased lower anterior facial height. These findings generally coincided with those for white subjects, however, there was no conclusive evidence in this study regarding the contribution of the upper anterior facial height or the posterior facial height to the AOB deformity.