[in Japanese]

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Several clinical trials are ongoing to evaluate induction chemotherapy and immunotherapy for locally advanced head and neck squamous cell carcinoma （HNSCC） including oral cancer, with the aim of improving survival and functional outcomes. Our tumor-immune microenvironmental analyses based on multiplex immunohistochemistry and image cytometry revealed the presence of three types of immune characteristics, which were associated with the efficacy of induction chemotherapy in locally advanced HNSCC. Tissue biomarker-guided patient selection can optimize future treatment strategies including induction chemotherapy/immunotherapy and surgical procedures in oral cancer.

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[in Japanese]

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Treatment methods for distant metastasis of squamous cell carcinoma of the head and neck include surgery, radiation, and chemotherapy, but sufficient consensus has not been obtained. We classified cases of distant metastatic lesions of squamous cell carcinoma of the head and neck into surgical treatment and non-surgical treatment groups, and compared the treatment results. The 1-year and 3-year survival rates in the surgical treatment group were 100％ and 86.4％ and in the non-surgical treatment group were 88.9％ and 19.2％. Surgical treatment had a good prognosis and no notable complications were observed. Surgical treatment is considered to be safe and provide a complete cure. With the progress of various treatments, the importance of multimodal therapy for the treatment of distant metastasis is increasing; it is considered necessary to propose a treatment policy considering the pathological condition.

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This study was conducted to evaluate the clinical outcomes of 53 patients with T3N0M0 larynx squamous cell carcinoma in our hospital between May 2006 and March 2019. The subjects were 48 men and 5 women, ranging in age from 47 to 88 years, with mean age of 72 years. The treatment was surgery in 26 patients, chemoradiotherapy （CRT） in 17 patients, and radiotherapy alone （RT） in 10 patients. The 3-year overall survival （OS） rate was 79.2％, and the 3-year disease-specific survival （DSS） rate was 84.4％. The total 3-year larynx preservation rate was 37.3％, 48％ for RT cases, and 81.6％ for CRT cases. Treatment with chemoradiotherapy improved larynx preservation rate versus radiotherapy alone （p＜ 0.05）. The 3-year OS rate was 82.2％ for surgery cases, 94.1％ for CRT cases, and 48％ for RT cases. Our therapeutic approach of using surgery or CRT showed successful outcomes for OS and DSS.

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Surgical resection is a standard treatment for lower gingiva squamous cell carcinoma. We retrospectively investigated the clinical outcomes of 28 patients with lower gingiva squamous cell carcinoma treated with surgery. The 5-year overall survival （OS）, disease-free survival （DFS）, and disease-specific survival （DSS） rates of all patients （n＝28） were 68％, 54％, and 80％, respectively. The 5-year DSS rate was poorer in pT4 compared with pT1/pT2/pT3 （p＜0.05）. No significant differences were found in patients with pN（−） and pN（＋） receiving neck dissection （p＝0.20）. In patients with pT4 disease, the treatment outcomes were not satisfactory and local recurrence was the direct cause of mortality. Therefore, adjuvant postoperative therapy should be recommended to improve the prognosis.

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Malignant tumors originating from thyroglossal duct cysts are rare, accounting for about 1％ of such cases, and most of them are diagnosed as papillary carcinomas; squamous cell carcinomas are extremely rare, accounting for about 5％ of malignant cases. In this paper, we report a case of squamous cell carcinoma thought to be derived from a thyroglossal duct cyst which required tumor resection with total laryngectomy. A 69-year-old woman presented to us with hoarseness, swelling and tenderness in the lower part of the submental region. Contrast-enhanced computed tomography （CT） and contrast-enhanced magnetic resonance imaging （MRI） suggested a disruption of the thyroglossal duct cyst with a neoplastic lesion. The diagnosis of squamous cell carcinoma was confirmed based on puncture aspiration cytology and tissue biopsies. The tumor had invaded into the larynx. The patient subsequently underwent anterior cervical malignant tumor resection including total laryngectomy. Comprehensive preoperative and postoperative histological analyses suggested that the squamous cell carcinoma had originated from a thyroglossal duct cyst. In cases of squamous cell carcinoma derived from thyroglossal duct cysts, the Sistrunk method alone is not always sufficient for tumor control. Total laryngectomy could be required in cases with laryngeal invasion of squamous cell carcinoma.

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We report our experience with a case of parathyroid carcinoma in which hypercalcemia was not apparent preoperatively. The patient was a 73-year-old woman. She was referred to the Department of Nephrology at our hospital for treatment during the induction phase of hemodialysis, and during treatment, a high intact PTH and left parathyroid tumor was noted. The patient had already been prescribed cinacalcet, and hypercalcemia was not observed. The patient did not wish to have surgery at first but later underwent left epithelial body resection, and the pathological diagnosis was parathyroid carcinoma. Conventionally, hypercalcemia is one of the findings that can raise suspicion of parathyroid carcinoma, but in this case, calcimimetic therapy was started before the hypercalcemia worsened, and it did not become apparent. Head and neck surgeons need to deepen their understanding of medical treatment in addition to surgery.

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Most schwannomas occur singly, but there are rare cases of multiple tumors in multiple nerves or in the same nerve. In this report, we describe our experience with a vagus nerve schwannoma that formed a bead-like appearance and reached a total length of 18cm. The patient was a 31-year-old man. His chief complaint was a left cervical tumor. Four years ago, he had become aware of a tumor in his left neck, and examined it closely. A schwannoma was suspected, and the patient was placed on a course of observation. After that, the tumor gradually increased in size from the first to second cervical vertebrae on the cephalic side to the height of the upper mediastinum on the caudal side, and the patient came to our center.
In this case, we performed an inter-capsular resection, but it was difficult to dissect the contiguous area between the tumors, and laryngeal paralysis occurred after the surgery.
Although bead-like schwannomas in the head and neck region are extremely rare and can be easily removed by total resection including the originating nerve, as this tumor is basically benign, inter-capsular resection may be an option to preserve nerve function after surgery.

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There are few reports on malignant tumors of an accessory parotid gland （APG）, and even fewer reports on salivary duct carcinoma （SDC） of APG. We present herein three cases of SDC arising from APG and a review of the literature.
All three patients underwent surgical resection, and none showed preoperative facial nerve paralysis. However, resection of the buccal branch of the facial nerve was required in all patients. Neck dissection was performed for late cervical lymph node metastasis in two patients, and postoperative radiotherapy was performed in the two patients with tumor invasion close to the resection margin or metastatic neck lymph node with extranodal extension. The primary lesion and neck were controlled in all three patients. However, distant metastasis was observed in two patients.
There are few reported cases of SDC arising from APG. It is important to consider appropriate treatment management.

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Auditory canal cancers are extremely rare and occur in only 1 per 1 million individuals. An external auditory canal carcinoma is the most common type of auditory canal cancer, accounting for approximately 0.2％ of all head and neck cancers. Histopathologically, squamous cell carcinoma is the most common type; other types include adenoid cystic carcinoma, basal cell carcinoma, malignant melanoma, and adenocarcinoma. Usually, adenoid cystic carcinoma shows relatively slow tumor growth, frequent local recurrence, distant metastasis, and resistance to radiotherapy and anticancer drug treatment. Therefore, surgery is the only therapeutic option for this histopathological cancer type, which is associated with poor prognosis. In this study, we report two cases of adenoid cystic carcinoma of the external auditory canal cartilage in patients who were successfully treated surgically.
Case 1: An 81-year-old man was referred to our hospital for additional resection of an adenoid cystic carcinoma with positive margins after removal of a right ear canal mass at another hospital. General anesthesia was contraindicated in this patient with diminished respiratory function owing to a history of pulmonary tuberculosis; therefore, we performed partial temporal bone resection under local anesthesia. No local recurrence was observed 15 months postoperatively.
Case 2: A 69-year-old man was referred to our hospital for comprehensive evaluation of persistent left ear pain. Biopsy findings revealed adenoid cystic carcinoma of the left external auditory canal, and we performed lateral temporal bone resection under general anesthesia. No local recurrence was observed 12 months postoperatively. Adenoid cystic carcinoma of the external auditory canal is rare; therefore, diagnosis is often delayed, and currently there is no established therapy, including surgical treatment. We report two rare cases of this malignancy, together with a review of the literature.

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Malignant tumors occurring in the palatine tonsils are most commonly primary and rarely metastatic. Herein, we present a case of tonsillar metastasis of hepatocellular carcinoma in an 80-year-old man. The patient presented at our hospital with a chief complaint of persistent bleeding from the oral cavity. On initial examination, a neoplastic lesion with white moss was observed on the right palatine tonsil. Following right palatine tonsillectomy, histopathological examination revealed atypical cells with enlarged nuclei forming a chord-like structure, suggesting metastasis of hepatocellular carcinoma. Fluorodeoxyglucose positron emission tomography–computed tomography performed to determine the tumor’s primary site showed accumulation in the left liver lobe. The patient underwent partial hepatectomy at the Department of Gastrointestinal Surgery. Since there was no obvious metastasis other than tonsillar, the patient is currently under follow-up observation.

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Surgical resection is one of the salvage treatment options for local recurrence or residual nasopharyngeal cancer and secondary cancer in the nasopharynx. Because of the anatomical complexity of the nasopharynx, the approach is limited and it is also difficult to secure a sufficient margin. We report a case of radiation-induced sarcoma that occurred 14 years after chemoradiotherapy as the initial treatment for nasopharyngeal cancer. The tumor, which arose from the superior and posterior wall of the nasopharynx, was resected via the transpalatal approach with mandibular swing combined with nasal endoscopy. By inserting instruments from two insertion paths, we obtained a good field of view and operability.
Previous reports about salvage surgery for nasopharyngeal malignant tumors have been limited in Japan; this procedure is considered to be a useful approach to the nasopharynx.

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Surgical resection of supragingival and hard palate tumors often requires functional reconstruction, such as the creation of a maxillary denture or flap reconstruction, because the postoperative connection of the oral cavity and nasal sinuses results in dysfunctions such as chewing, swallowing, and dysarthria. We report here a case of mucosal malignant melanoma of the hard palate that was cured without functional impairment by preservation of the nasal mucosa. The patient was treated surgically with a diagnosis of mucosal malignant melanoma cT3N0M0 without bone invasion. In the surgery, the nasal septum and nasal floor mucosa were preserved endoscopically, and the palatal mucosa, maxilla, palatine bone, and vomer were removed en bloc. In addition, the MCFP （Mucosal defect Covered with Fibrin glue and Polyglycolic acid sheet） technique was performed with nasal mucosal lining. Recovery was possible without functional impairment without the use of flap reconstruction or maxillary dentures.

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A 26-year-old male visited our hospital due to anterior cervical swelling. MRI showed multiple flow voids within the lesion in the left lobe of the thyroid gland, and arteriovenous malformation （AVM） was suspected. The lesion extended toward the larynx, and its vascular pedicle was anastomosed to the superior laryngeal artery. Two days before surgery, angiography followed by arterial embolization was performed. Although the AVM was fed by superior and inferior thyroid and superior laryngeal arteries, the inferior thyroid artery was selectively embolized to avoid serious bleeding during the surgery. The AVM was resected with the left lobe of the thyroid gland following ligations of the feeding arteries. The caudolateral part of the thyroid cartilage was transiently removed, and then the AVM was extirpated. The inferior laryngeal nerve was identified and traced to the larynx using a nerve integrity monitor. Although immobility of the unilateral vocal fold was transiently observed, mobility was regained four months after the surgery.

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