Youngjin Ahn

OK-432 sclerotherapy in head and neck lymphangiomas: Long-term follow-up result

INTRODUCTION: Nonsurgical treatments, such as sclerotherapy have been attempted for head and neck lymphagiomas. Of the available sclerosing agents, picibanil has shown satisfactory short-term treatment results in many studies, but no study has presented long-term treatment results. Accordingly, in the present study, the authors retrospectively reviewed the long-term treatment results of picibanil sclerotherapy. MATERIALS AND METHODS: Fifty-five lymphangioma patients who underwent picibanil sclerotherapy were enrolled. Data about initial and long-term response, recurrence, and excision rate were collected. RESULTS: Initial response rates were 83.5 percent and long-term response rates were 76.3 percent. CONCLUSION: Initial and the long-term response rate were equally good for lymphangioma.

Molecular epidemiology of Newcastle disease in Republic of Korea

Twenty-three strains of Newcastle disease virus (NDV) isolated between 1988 and 1999 in Republic of Korea were studied by partial nucleotide sequencing of fusion (F) gene and phylogenetic analysis. Most of Korean strains formed a distinctive cluster in genotype VI and they were genetically distant (4.0-8.7%) from other subtypes (a, b, c, d, and e), and termed provisionally VIf. Some Korean strains isolated in 1995 were grouped into genotype VIIa and they were closer to Taiwan strains than western Europe. The results suggest that the genotype VIf strains have been maintained by enzootic infections during the past decade, while genotype VIIa appears to be introduced more recently in Republic of Korea.

Primary Tracheal Tumors: Review of 37 Cases

Introduction: Primary tracheal tumors are rare, and composed of various benign and malignant pathologies. Although nationwide epidemiologic studies were reported in western population, study about the oriental population is lacking. The aims of this study were to establish the clinical manifestations and treatment outcomes of primary tracheal tumors and explore the prognostic variables for malignant tracheal tumors. Methods: From January 1989 through December 2006, 37 patients (14 with benign tumors, 23 with malignant tumors) were treated in a tertiary referral center. Retrospective review of medical records was performed. Results: Benign tumors comprised of various pathologies. Except the papilloma cases (n = 3), all of them were managed successfully without recurrence. Squamous cell carcinomas (n = 11) and adenoid cystic carcinomas (n = 9) comprised most of the malignant tumors. Clinical stage was a statistically significant prognostic variable (p = 0.016). Five-year overall survival rate was 41.1% for squamous cell carcinoma and 45.7% for adenoid cystic carcinoma and no statistically significant difference (p = 0.673) was observed. Conclusion: Papillomas were difficult to manage, however, other benign tumors were successfully treated. Among malignant tumors, surgery should be considered as the first choice of treatment, regardless of the histologic type, if the tumors are resectable.

Schwannoma Mimicking Laryngocele

A schwannoma of the larynx is a rare benign tumor that usually presents as a submucosal mass in the pyriform sinus and the aryepiglottic space, and this type of schwannoma constitutes a diagnostic and therapeutic challenge for otolaryngologists. We present here two cases of supraglottic schwannomas that were misdiagnosed as laryngoceles. Both were excised through a lateral thyrotomy approach without a tracheostomy, and the laryngeal function was successfully maintained. We discuss the clinical and imaging findings and the management of this rare neoplasm with focusing on the differential diagnosis of laryngeal schwannoma and laryngocele. We also review the relevant medical literature.

Characterization of a chicken embryo-adapted H9N2 subtype avian influenza virus.

The low pathogenic avian influenza (LPAI) caused by H9N2 virus has generated economic losses in the Ko- rean poultry industry since 1999, but field isolates could not be used for killed oil emulsion vaccine directly because of low productivity in embryonated chicken eggs (ECE). Therefore, we established a vaccine strain, KBNP-0028, by passage through ECE with allantoic fluid showing the highest volume and titer. KBNP-0028 possessed 158 N-glycan on hemag- glutinin (HA) as its parent strain, but acquired a 16 amino acid deletion in the stalk region of neuraminidase (16-del NA) as a result of balancing with the glycosylated HA. KBNP-0028 was sufficiently productive in ECE to be compared with the A/Puerto Rico/8/34 (PR8) strain and immunogenic enough to induce high antibody titers. The antibodies inhibited hemagglutination of recent field isolates as highly as they inhibited KBNP-0028. Genome analysis revealed that KBNP- 0028 carried no known mutation relevant to virulence in mammalian. In conclusion, KBNP-0028 is a promising vaccine candidate for prevention of the LPAI in the Republic of Korea.

Measurement of Cross-Sectional Dimensions of the Cricoid Cartilage: A Computed Tomographic Study:

Objectives: We measured the cross-sectional dimensions of the cricoid cartilage and degrees of ossification of the marrow space for designing a cricoid implant. Methods: We reviewed 100 age- and sex-matched neck computed tomography scans that were performed at Seoul National University Hospital from 2001 to 2005. Under a standardized computed tomography window setting, the height of the cricoid cartilage marrow and the thickness of the marrow space and the ossified inner and outer cortices were measured by one observer. Results: The mean height of the cricoid cartilage marrow was 13.6 mm (range, 5.5 to 20.5 mm) in women and 17.5 mm (range, 13.0 to 24.5 mm) in men. The mean thickness of the cricoid cartilage marrow was 3.17 mm (range, 1.22 to 4.75 mm) in women and 5.13 mm (range, 3.42 to 7.60 mm) in men. We also observed that women in general have a higher density of the cricoid marrow than men; 4 women and 1 man had a markedly denser marrow space. There were individual variations in size and density of the cricoid marrow. Conclusions: Human adult cricoid cartilages have sufficient marrow space for cricoid implantation. Preoperative evaluation of the size and density of the cricoid marrow is recommended for individual application of the cricoid implant.

Gastric choristoma of the oropharynx.

Heterotopic gastric mucosa tissue is also called gastric choristoma, and this type of lesion can be found anywhere in the alimentary tract. However, gastric choristoma in the pharynx is very rare; only 10 cases of pharyngeal gastric choristoma have been reported in the English medical literature. A 32-yr-old woman was referred to our institution for the evaluation of a large mass that originated from the posterior wall of the oropharynx. The mass did not cause any symptoms except for the occasional sensation of a foreign body. Gadolinium-enhanced T1 weighted imaging showed a 5 cm-sized mass with central enhancement and hypointense portions, yet the radiological diagnosis was not clear. Transoral mass excision was performed with using electrocautery for making the diagnosis and for treating the mass. The microscopic analysis revealed gastric choristoma.