Background: The molecular pathogenesis of hereditary medullary thyroid carcinoma is well known to be associated with germ-line mutation in the RET proto-oncogene and sporadic medullary thyroid carcinoma has been shown to carry somatic RET mutation especially in exon 13 and 16. The aim of this study is to evaluate the genetic background in the pathogenesis of the sporadic medullary thyroid carcinoma which shows extremely high incidence in Korea. Materials and Methods: Direct DNA sequencing for RET exon 13 and 16, as well as immunohistochemistrical assay for a monoclonal RET antibody were performed from 20 cases of archival tissues of medullary thyroid carcinoma. Results: Monoclonal RET antibody with C-terminal epitope showed comparatively stronger expression in tumor cells than in normal tissues and immunoreactive area in the tumor was $66.0{\pm}40.1%$. Direct sequencing of RET exon 13 revealed 4 cases of mis-sense mutations in Codon 778, Codon 767, and both in Codon 768 and 778. One case showed a silent mutation (ACG-ACT) in RET exon 16 (Codon 926). Conclusions: The strong RET immunoreactivity of medullary thyroid carcinoma may suggest that there could be a genetic alteration in oncoprotein level. RET proto-oncogene mutation may be involved in the evolutional process of medullary thyroid carcinoma in the aspect of molecular basis.

Objectives: Expression of HMGI(Y), a nucleoprotein that binds to A/T rich sequences in the minor groove of the DNA helix, is observed in neoplastically transformed cells but not in normal cells. We have analyzed HMGI(Y), p53 expression and Ki-67 labelling index in squamous cell carcinomas of the head and neck, and evaluated its clinicopathologic significance. Materials and Methods: 40 cases of squamous cell carcinoma of the head and neck were entered on the study of immunohistochemical stains for HMGI(Y), p53 and Ki-67. We analyzed the relationship between HMGI(Y), p53, Ki-67 expression and age, sex, primary tumor site, stage, survival rate, recurrence. Results: HMGI(Y) expression evidenced by immunohistochemical staining was observed in 35 of 40 (87.5%) squamous cell carcinoma of the head and neck. But no significant correlation was observed between HMGI(Y) expression and other clinical factors such as primary site, tumor stage, differenciation, cervical lymph node, metastasis, recurrence and immunohistochemical status of p53. The Ki-67 labelling index was significantly correlated with recurrence and HMGI(Y) expression (p<0.05). Conclusion: This results suggest the Ki-67 is a good prognostic factor and the HMGI(Y) expression plays some roles in carcinogenesis and cellular proliferation of squamous cell carcinoma of the head and neck. HMGI(Y) gene can be used as a cancer marker, the correlation between the gene expression and the prognosis of the cancer patient should be proved in the future studies.

Background and Objectives: The expression of telomerase, a ribonucleoprotein complex, has been detected in tissues from many human cancers, but not in the majority of normal tissues except germ cell. It is believed that the activation of telomerase is linked to celluar immortality and may playa role in tumorigenesis. Human telomerase reverse transcriptase (hTERT) has been identified as a putative catalytic subunit of human telomerase and its expression is closely correlated with telomease activity. We studied the expression of hTERT in head and neck squamous cell carcinoma (HNSCC) and resection margin by immunohistochemistry for hTERT and evaluate the correlation between hTERT expression and clinical data in HNSCC. Materials and Methods: We performed a immunohistochemistry in 17 cases of HNSCC and 10 cases of resection margins, histologically normal. The correlations between the hTERT expression and the clinical data in HNSCC were analyzed. Result: hTERT immunoreactivities were detected in 14 of 17 (82.4%) HNSCC, 1 of 10 (10%) resection margin. No correlation was observed between clinical data and hTERT expression in HNSCC. Conclusion: hTERT is activated in HNSCC and its expression is independent from clinical data of patients.

Mutation of the P53 tumor suppressor gene playa major role in the development of many carcinomas, namely in the colon, breast and bladder, whereas the role played by such mutations in thyroid carcinogenesis remains controversial. Vascular endothelial growth factor (VEGF) induces proliferation of endothelial cells, stimulates angiogenesis, and increases vascular permeability. Increased VEGF expression has been associated with poor clinical outcomes in many malignancies E-cadherin, a calcium-dependent transmembrane glycoprotein, is an adhesion molecule Expression of p53, VEGF and E-cadherin was assessed immunohistochemically in 19 tall columnar variant of papillary carcinoma, 24 common papillary carcinoma and 7 follicular carcinoma. The aim of this study was to evaluate the expression of P53,VEGF and E-cadherin as a potential maker for the prognosis of thyroid carcinomas. The results are as follows: 1) There were no significance in any clinical parameters examined among tall columnar variant of papillary carcinoma, common papillary carcinoma and follicular carcinoma. 2) The expression of P53 demonstrated low in tall columnar variant of papillary carcinoma, common papillary carcinoma and follicular carcinoma, but a significantly high in regional lymph node metastasis. 3) The expression of VEGF demonstrated a significantly high in regional lymph node metastasis than those without metastasis in papillary thyroid carcinoma. 4) The expression of E-cadherin demonstrated less often among papillary carcinomas with lymph node metastasis than in those without metastasis in papillary thyroid carcinoma. In conclusion, it is suggested that VEGF and E-cadherin will be useful for the diagnosis of thyroid carcinoma and serves as a biological marker for thyroid carcinoma lymph node metastasis.

Objective: To determine the effectiveness and toxicity of chemoradiation therapy in nasopharyngeal carcinoma by comparing with radiation therapy alone. Materials and Methods: Between October 1989 and July 2000, One hundred eleven patients with newly diagnosed and histologically proven nasopharyngeal carcinoma treated in Department of Radiation Oncology, Asan Medical Center were retrospectively reviewed. Forty-five patients were treated with radiation therapy alone (Group I) and 66 patients were treated with radiation therapy and concurrent cisplatin (Group II). Cisplatin was administered once a week, on the first day of each successive week of treatment, starting on day 1 of radiation therapy and given as a intravenous bolus at a dose of $20mg/m^2$ of body-surface area. Radiation therapy was given in doses of 1.8Gy, once a day, 5 days per week with 4MV or 6 MV photons. Initial field was received a total of 60Gy and a primary tumor and enlarged lymph nodes were boosted with an high dose intracavitory brachytherapy and 3D conformal therapy. Results: The complete response rate was 86.7% in Group I, and was 90.9% in Group II. The 5 year overall survival rate for Group I was 60% and for Group II was 45% (p=0.2520). The 5 year disease free survival rate was 52% versus 45%, respectively (p=0.7507). The median follow up was 44 months versus 34 months, respectively. Conclusion: Analysis of the III patients showed no significant difference in disease free survival and overall survival in two treatment group. This retrospective analysis did not demonstrate benefit with concurrent chemoradiation using cisplatin at a dose of $20mg/m^2$ of body-surface area in treatment result than radiation alone.

Background and Objectives: To determine if laser endoscopic microsurgery is a reliable and appropriate approach in the treatment of laryngeal carcinomas. Materials and Methods: Retrospective study of 62 patients treated with CO2 laser from June 1988 to November 2000 at Seoul National University Hospital for laryngeal squamous cell carcinoma. All patients were treated with curative intention. Fifty three untreated patients with laryngeal carcinoma (39 glottic and 14 supraglottic carcinoma patients) had primary carbon dioxide laser microsurgery. Nine radiation failure patients were treated. Postoperative radiotheray was done for 17 patients. Neck dissection was performed simultaneously for 4 supraglottic cases with cervical nodal metastasis. Mean follow-up duration was 40 months. Results: In primary laser surgery group, distribution of tumors (American Joint Committee on Cancer, 1997) were 38 cases with Tl, 13 cases with T2, 2 cases with T3. Cure rate was 88.7%(47/53) and local control rate was 92.5%(49/53). Larynx was preserved in 94%(50/53) of patients. The overall 5-year survival rate(Kaplan-Meier) was 81.5%. In radiation failure group, 56% of patients were recurred after laser surgery. Conclusion: Laser surgery could be a better treatment modality for early laryngeal cancers and selected advanced cases. Additional radiation therapy should be considered if resection margin is not satisfactory.

Background and Objectives: To evaluate the efficacy of the neoadjuvant chemotherapy and radiation therapy in treatment of patients with advanced hypopharyngeal cancer, which is notorious for its poor prognosis and severe surgical morbidity with functional deficits. Materials and Methods: Medical records and radiologic findings of 107 patients with squamous cell carcinoma of the hypopharynx, Stage III or IV (AJCC, 1997), were retrospectively reviewed. Results: Neoadjuvant chemotherapy followed by radiation therapy showed 74% complete remission (CR) rate. The patients who did not show CR after chemotherapy had a high likelihood of treatment failure, even though they achieved CR following subsequent radiotherapy. Twenty-eight of 57 patients were able to preserve their larynges for more than three years by chemotherapy and radiation. Conclusions: This approach appeared to be as effective as radical surgery with postoperative radiation therapy without comprising of survival. To improve the cure rates, we need to develop better strategies to increase CR rates with chemotherapy and determine the best treatment option for patients who are partially or nonresponsive to chemotherapy.

Background: Free flaps have become a very important role in the ablative head and neck surgery with functional preservation of defect sites. The forearm free flap has many advantage of lack of bulk, ease of dissection, vascularity, and malleability. Patients and Methods: A review of 51 radial forearm free flaps performed between may 1990 and feburary 2001 at the Korea University was undertaken to determine outcome. Patient age ranged 27 to 72 years (mean 56). There were 44 men and 7 women. The most prevalent neoplasm was squamous cell carcinoma. Results: The tans verse cervical artery and the external jugular vein were the most frequent receipient sites for microvascular anastomosis. Total flap loss occurred in 2 cases (4%) and other complications were seen in 42%. Fifteen patients received preoperative irradiation and the complication was higher than non-irradiation patients, but statistically not significant. Conclusion: The radial forearm free flap offers a variety of reconstructive options for head and neck. Its low flap loss and complication rates offer the best choice for reconstruction of defect of head and neck malignancy.

Objectives: Thyroid cancer is the most common endocrine malignancy with favorable histologic and prognostic characteristics. Total or near total thyroidectomy has been used as a standard surgical procedure. The aims of this study are to determine the extent of resection of thyroid gland and to find the influencing factors of lymph node metastasis. Materials and Methods: The authors reviewed the records of 194 patients of thyroid cancer surgically treated at Department of General Surgery, Inje University Busan Paik Hospital from January, 1996 to December, 2000. Pathologic classifications, surgical procedures, and lymph node metastasis were analyzed. Results: There were 163 women and 31 men. The age ranged from 12 to 79 years old (mean age 43.2 years). The histological classifications of 194 cases revealed papillary cancer in 171 cases (88.1%), follicular cancer in 17 cases (8.8%), undifferentiated cancer in 3 cases (1.6%), medullary cancer in 2 cases (1.0%) and mixed cancer in 1 case (0.5%). Among the 194 patients, lobectomy was perfomed in 31 patients, subtotal thyroidectomy in 30 patients, near total thyroidectomy in 82 patients and total thyroidectomy in 51 patients. In the subgroup of papillary carcinoma 141 cases with lymph node dissection, lymph node metastasis had no statistical significance according to sex, age and primary tumor size. Conclusions: The mainly performed surgical procedures were total thyroidectomy and near total thyroidectomy. In thyroid cancer surgery, the extent of resection was influenced by age, differentiation and primary tumor size. The lymph node dissection should be decided by lymph node metastasis identified by preoperative radiologic evaluation or intraoperative lymph node findings.

Background and Objective: Even though major salivary gland tumor is a rare disease, the diversity of histopathologic characteristics makes treatment decisions difficult. The aim of this study is to analysis the clinical experience of our major salivary gland tumor and to suggest a guideline of treatment. Materials and Method: Sixty-eight major salivary gland tumors and tumor-like glandular enlargements treated at Sanggye Paik Hospital during the past seven years between June, 1995 and January, 2002 are analyzed for histopathologic diagnosis, treatment modality, clinical manifestation, local control, and treatment-related morbidity, recurrence rate, retrospectively. Results: In twenty-eight patients the swellings were diagnosed as non-tumorous condition. The clinical features, diagnostic and surgical management of fourty salivary neoplasms involving the parotid and submandibular glands are correlated with their histological features. Conclusion: We have concluded that salivary gland neoplasms are needed multimodal treatment, because of their highly variable biologic behavior in each tumor type. Thirty-four cases were benign and six cases were malignant. Most of benign cases were pleomorphic adenoma and they showed wide age-distribution. In six malignant cases, there were acinic cell carcinoma, adenocarcinoma, carcinoma ex-plemorphic adenoma, myoepithelioma, and adenoid cystic carcinoma.

Objectives: Three classic treatment modalities have been used to treat Graves' disease: antithyroid medication, radioiodine ablation, and subtotal thyroidectomy. Postoperative thyroid functions were studied in patients with Graves' disease treated by subtotal thyroidectomy to evaluate the superiority of surgical treatment. Materials and Methods: One hundred fourty patients of Graves' disease were analysed retrospectively in follow-up for more than three years following subtotal thyroidectomy. Postoperative serum levels of $T_3,\;T_4, TSH, TSH-R Ab, free $T_4$, were evaluated to watch hypo- or hyperthyroidsm. Results: In the evaluation of preop- and postoperative thyroid function after three years of subtotal thyroidectomy, $T_3$ was changed from $464.10{\pm}196.16ng/dl$ to $140.41{\pm}76.56ng/dl$ in mean value, $T_4$ was changed from $20.76{\pm}7.98{\mu}g/dl$ to $9.54{\pm}4.02{\mu}g/dl$, $TSHT_3$ was changed from $0.55{\pm}4.42{\mu}u/ml$ to $4.96{\pm}7.20{\mu}u/ml$, TSH-R Ab was changed from $41.6{\pm}28.27%$ to $28.7{\pm}28.79%$ and free $T_4$ was changed from $4.45{\pm}2.33ng/dl$ to $1.44{\pm}0.69ng/dl$ in mean value. Euthyroidism was noted in 118 patients(84.3%), overt hyperthyroidism in 6 patiens(4.3%), latent hyperthyroidism in 8 patients(5.7%), overt hypothyroidism in 2 patint(1.4%), and latent hypothyroidism in 6 patients(4.3%). Of surgical complications, permanant hypoparathyroidism was found in one patient, recurrent laryngeal nerve injury in two patients, postoprative bleeding with reoperation in two patients, and death in one patient. Conclusion: The thyroid function after subtotal thyroidectomy in diffuse toxic goiter is normal level (euthyroidism) in 84.3% and low recurrence rate of hyperthyroidism is showed with rare surgical complication. Therefore, subtotal thyroidectomy in diffuse toxic goiter is more effective and safe than RI or longterm ATD treatment, if the operation is performed by skillful surgeon.

Background and Objectives: Recently the tenn 'papillary microcarcinoma' has been proposed to designate carcinoma of 10 mm or less in diameter. In some cases, cervical lymph node metastasis preceding the occurrence of the primary tumor may be the first and sole manifestation of the disease. The objective of this study is to assess the clinical features of cervical metastasis in papillary microcarcinoma of thyroid glands. Materials and Methods: 9 cases with papillary microcarcinoma with neck metastasis were analyzed retrospectively. 5 cases are men and 4 are women. All patients complained of painless, movable neck mass. The symptom had been present from 1 month to 36 months. We reviewed clinical history, imaging studies, the results of fine needle aspiration, the surgical method, the pathologic results. Results: In 9 cases, no abnormalities of the thyroid gland were shown by imaging studies and thyroid scan. 3 cases were diagnosed by fine needle aspiration cytology. the others were not. Total thyroidectomy and neck dissection were performed in 9 cases and then pathology reports showed 2 case of multiple, 2 case of contralateral single and 5 cases of unilateral single thyroid microcarcinoma. They have no recurrence during follow-up period. Conclusions: Cervical metastasis from papillary microcarcinoma is variable clinical manifestation. The diagnosis of cervical metastasis from papillary microcarcinoma should be considered in patient with neck mass. We recommend total thyroidectomy with neck dissection and postoperative radioactive iodine ablation therapy in neck metastasis from papillary thyroid microcarcinoma.

Background and Objectives: The tracheotomy is one of the most essential surgical procedures performed in the intensive care unit (ICU). The tracheal stenosis, as a complication following endotracheal intubation or tracheotomy, has been the subject of considerable recent investigation. Many different methods have been developed to avoid the tracheal stenosis but there is still controversy about the tracheal incisions. We had performed tracheotomy using a vertical elliptical tracheal incision in the ICU to evaluate its efficiency and safety. Materials and Methods: 191 patients who underwent the tracheotomy in the ICU between 1995 and 2000 were reviewed retrospectively by chart records and interviews. Results: The complications were reported such as bleeding, infection, subcutaneous emphysema, pneumothorax, tracheoesophageal fistula and tracheal stenosis. The total numbers of complications were 35 cases (18.3%) and the tracheal stenosis was developed in 4 patients. The characteristics of tracheal stenosis are as follows. Conclusion: The vertical elliptical tracheal incision is the safe and reliable methods in ICU patients compared with other methods, but other factors are also important in preventing the complications.

Temporoparietal fascial flap (TPFF) has been used in the reconstruction of a broad spectrum of complex defect of head & neck it can be used as pedicled flap or free flap. TPFF is extensively is good for reconstruction of auricular defects because it is fascial flap with ease of covering irregular surface. TPFF is supplied by the superficial temporal artery & vein and innervated by zygomatico-temporal branch of facial nerve and auriculotemporal nerve. The flap ranges from 2-4mm in thickness and can be harvested up to 17x14cm wide, it can include calvarian bone and enables primary closure of donor site. We carried out reconstruction of oral cavity defects by means of TPFF with a satisfactory result in two cases of oral cavity cancer.

Thyroglossal duct cyst is a congenital anomaly generally appearing as an asymptomatic midline neck mass. Generally, the duct cyst is benign, but 1 percent of cases may be malignant. These present the same histologic types as thyroid carcinomas. The most common pathologic type is papillary carcinoma. Regional lymph node metastasis of papillary carcinomas in thyroglossal cyst occurs in 7.7 percent of cases. Prognosis of papillary carcinoma is excellent. The treatment has been quite variable, but the most common initial treatment is Sistrunk's operation. Adequate excision of cyst and its tract including the mid-portion of the hyoid bone is the treatment of choice. We experienced two cases of papillary carcinoma arising in thyroglossal duct cyst between 1986 and 2002.

Plunging ranula is occured in about 10% of all ranula cases although surgery is the first choice therapy. However, frequent recurrences of the disease due to insufficient surgery have been reported, and various therapies have been designed in addition to surgery. We here report a case on whom we conducted intralesional injection of OK-432 for recurrent plunging ranula. A 36-year-old man was admitted who had a 2-months history of swelling of right submandibular area. He had been operated for right plunging ranula twice, 7 years ago. Under fluoroscopic guidance, contents of the ranula were aspirated and OK-432 solution was injected twice with 3-week interval. Examination after 6 weeks showed that the cystic ranula seen before therapy had disappeared completely and no recurrence was encountered after 18months. Therefore the intralesional injection of OK-432 is effective method for treatment of the plunging ranula.

Malignant melanoma of the nasal cavity occurs rarely. Malignant melanoma, originated from the upper respiratory tract including nasal cavity, has clinical feature of local recurrence and easily metastasizes to regional or distant lymph nodes, lung, and liver. Malignant melanoma originated from nasal cavity frequently shows tumor cell invasion, ulceration, or infection. Owing to these characteristics, complete surgical excision of the malignant melanoma in nasal cavity is not easy. And also the prognosis of this tumor is not so good because of a high recurrence rate. Recently the authors have recently experienced a case of malignant melanoma originated from the inferior turbinate, which was treated with lateral rhinectomy, total maxillectomy. The defect developed after surgical extirpation was reconstructed with rotational forehead flap.