Congenital malformations of the larynx, which is crucial for breathing and swallowing, are rare. To enable a better understanding of congenital laryngeal malformations, the prenatal development of the trachea and larynx is summarized, based on the classification described by Henick. It is followed by a review of the molecular-biological findings in recent studies focused on the development of trachea and larynx. The molecular mechanism of laryngeal development has not been well documented and needs to be elucidated by future research using conditional knockout mouse lines specific to the larynx.

Hearing loss of acute onset is rather rare in patients with multiple sclerosis. We encountered a case of multiple sclerosis with retrocochlear deafness of acute onset, which improved without any treatment.

A 16-year-old woman was referred to our hospital 1 day after she developed sudden hearing loss. She showed obvious waves of distortion product otoacoustic emission, despite pure-tone audiometry showing profound sensorineural hearing loss in her right ear. Auditory brainstem response showed normal peaks I and II and absence of subsequent peaks on the right side. T2-weighted magnetic resonance imaging (MRI) showed multiple high-intensity lesions in the cerebral white matter and no lesion within the right eight cranial nerve root. Speech audiometry showed 0% (100 dB) in the right ear, and both conventional and fixed-frequency tracings in the self-recording audiometry of Bekesy were classified as type IV according to the classification of Jerger. We diagnosed the patient as having retrocochlear deafness and referred her to the department of neurology. On MRI, a white matter attenuated inversion recovery (WAIR) sequence obtained using the double inversion recovery (DIR) method showed a lesion of the middle cerebellar peduncle. MRI of the spine showed multiple lesions in the left side of the spine. Examination of the cerebrospinal fluid showed a high IgG index and oligoclonal band positivity. Based on the findings, the patient was diagnosed as having multiple sclerosis. By day 40 after the onset of symptoms, both the subjective symptoms and the results of pure-tone audiometry improved gradually with no therapy. By day 158 after the onset of symptoms, the ABR showed the appearance of peak V. Speech audiometry showed a 100% (50 dB) result and the tracings on self-recording audiometry of Bekesy were classified as type I according to the classification of Jerger. Only by WAIR imaging could we recognize the lesion of the middle cerebellar peduncle. Therefore, when performing MRI fors patients with retrocochlear deafness, scanning using the DIR method should be considered.

Middle ear adenoma (MEA) is not commonly encountered in clinical practice. Most patients have non-specific symptoms, such as conductive hearing loss or ear fullness. Due to the rarity of the tumor, there is scarce literature on this tumor, and its classification is still under debate. In this report, we present three cases of MEA who visited Osaka University Hospital during the last 5 years. In the first case, the patient presented with otorrhea, conductive hearing loss, and thickening of the ear drum. Biopsy of the ear drum failed to yield a diagnosis preoperatively. We performed tympanoplasty with mastoidectomy for tumor removal and diagnosis, and histopathological examination of the resected specimen revealed the diagnosis of MEA. The second case was initially diagnosed as having chronic otitis media and underwent tympanoplasty with mastoidectomy, but histopathological examination of the granulation-like tissue revealed the diagnosis of MEA. In both these cases, a second-look surgery was performed 6–7 months after the first one, which revealed local recurrences that were removed. In the third case, the tumor was localized in the posterior part of the tympanic cavity. Preoperative transtympanic biopsy revealed the diagnosis of MEA. En bloc resection of the tumor was performed by the transcanal approach. In all of these three cases, histopathological examination with HE staining and immunohistochemical staining for synaptophysin, neuron-specific enolase (NSE) and chromogranin-A revealed the diagnosis of adenoma of the middle ear. Treatment of MEA is, in principle, complete tumor resection; however, there is a high risk of residual disease and recurrence, and long-term follow-up is required. It is difficult to distinguish MEA from carcinoid tumors, which may also recur and metastasize. The Ki 67 index, which is often used as an indicator of malignancy in the field of gastroenteropancreatic neuroendocrine tumors, may help in guiding appropriate management.

Herein, we report a case of isolated oculomotor nerve paralysis caused by a sphenoid sinus cyst. An 80-year-old man presented with right-sided ptosis, diplopia and occipital headache. He had unilateral ptosis and disturbance of the upward, downward and inward ocular movements, however, ophthalmologic examination showed neither visual impairment, nor pupillary dilatation. The symptoms were clearly caused by isolated right oculomotor nerve paralysis. Computed tomography (CT) and magnetic resonance imaging (MRI) revealed a lateral sphenoid sinus lesion with a smooth margin compressing the right cavernous sinus and shaving down the surface of the clivus. Based on a diagnosis of sphenoid sinus cyst, we performed endoscopic surgery under general anesthesia. The ocular movements became normal approximately 2 months after the operation and the right-sided ptosis disappeared within 6 months of the sugery. Since oculomotor nerve paralysis due to sphenoid sinus cyst is highly amenable to cure by endoscopic surgery, operation should be aggressively pursued for its treatment.

Lipomas are among the most common of soft tissue tumors, but they rarely occur in the oral cavity (2.2%). The most common site of occurrence is the cheek, followed by the tongue, lips, and gingiva; the oral floor is a relatively unusual site.

The patient was a 74-year-old man, who had first become aware of swelling of the oral floor without any other symptoms about 19 years earlier. He preferred not to have it examined further, but have it monitored over time instead. However, the mass increased in size over time, causing difficulty in speech, eating and closing of the mouth. Finally, he decided to undergo surgery. The tumor was completely excised via the transoral approach. The mass was 70 mm in diameter. Histopathological examination confirmed the tumor as a lipoma. This is the largest lipoma in the oral cavity reported over the last decade in Japan.

Even if it begins as a small and asymptomatic tumor, lipoma of the oral floor may grow to a large size and become symptomatic, causing difficulty in speech and eating. Thus, lipomas of the oral floor should be managed surgically as soon as possible.

Tongue cancer, the most common type of oral cancer, is a disease that is frequently encountered by head and neck surgeons in daily medical practice. Approximately 20% to 40% of patients with early tongue cancer (T1/T2 tumors) reportedly have latent lymph node metastases, even though clinically, these patients are staged as N0. Although the indications for prophylactic neck dissection are controversial, it is extremely important to consider the methods to control delayed cervical lymph node metastasis. Of 46 patients with early tongue cancer, 10 patients with delayed cervical lymph node metastasis were enrolled in this study. Lymph nodes which later turned out to be malignant and also normal lymph nodes in both the affected and unaffected areas were scanned by computed tomography (CT) at the initial visit. The CT values were calculated, and the results were compared in order to examine whether or not measurement of the CT values of the lymph nodes at the initial visit might be useful in screening for delayed cervical lymph node metastasis. Our findings revealed that the CT values of the lymph nodes in patients with secondary cervical lymph node metastasis were statiscally significantly lower as compared to those in the patients without lymph node metastases. Therefore, in the case of low CT values, the affected/unaffected lymph nodes on the CT images of in patients with clinical N0 may be occult metastatic lymph nodes. Salvage neck dissection may later become necessary in these patients if they develop secondary cervical lymph node metastasis.

Mammary analogue secretory carcinoma (MASC) is a unique pathological entity that was recently proposed, in 2010, by Skálová et al. as a salivary gland carcinoma harboring an ETV6-NTRK3 fusion gene. It has been pointed out that a proportion of cases diagnosed as acinic cell carcinoma are, in fact, cases of MASC, both conditions showing similar pathological features. Herein, we report 2 cases of MASC that were previously diagnosed as acinic cell carcinoma. One of the cases had the rare ETV6-X fusion gene. Both cases were treated by surgical resection and postoperative radiation. One of the cases has shown an uneventful clinical course for over 8 years, while the other developed local recurrence and has been receiving chemotherapy.

We clinically analyzed 20 MASC cases reported in Japan, including our cases. The most common primary site is the parotid gland, followed in frequency by the minor salivary glands. Lymph node metastasis was seen in 27% of cases. ETV6 gene mutations were observed in all the cases. The prognosis of MASC tends to be worse than that of acinic cell carcinoma. Surgical removal is the treatment of first choice.

Mucoepidermoid carcinoma (MEC) is one of the most common malignant tumors of the salivary glands, and the tumor is composed of mucous, squamous and intermediate cells. However, primary intraosseous MEC is an infrequent condition, in which location of the primary site is often delayed. We report a case of central MEC of the mandible. A 39-year-old man was admitted to our hospital with swelling of the lymph nodes in the left submandibular region. While fine-needle aspiration cytology of the lymph node showed metastatic adenocarcinoma, the primary site could not be detected by computed tomography, magnetic resonance imaging, positron emission tomography or gastrointestinal endoscopy. We performed modified radical neck dissection, and the histopathological diagnosis was MEC. Three months later, slight swelling of the left mandibular molar resion was observed, and a biopsy revealed the diagnosis of squamous cell carcinoma. We then performed left hemimandibulectomy, retropharyngeal lymph node dissection and right modified radical neck dissection, followed by reconstruction using a rectus abdominis myocutaneous flap. The histopathological diagnosis was high-grade MEC, and most of the lesion was located within the mandible. Even though the patient received postoperative adjuvant concomitant chemoradiotherapy with cisplatin, lung metastasis was detected, and the patient died 1 month later. Although central MEC of the mandible is an unusual tumor, careful examination with attention paid to the mandible should be performed, especially for ceses with an occult primary lesion.

We report two cases of thyroid papillary carcinoma with anterior chest wall fistula communicated with the mediastinum caused by lenvatinib. Both patients had previously undergone mediastinal dissection via median sternotomy and received external beam radiation therapy (EBRT) for locoregional recurrences in the chest. Lenvatinib, an antiangiogenic multitargeted tyrosine kinase inhibitor (TKI), was withdrawn, and both patients died of disease progression.

Lenvatinib is a valuable treatment option for cases of advanced differentiated thyroid cancer refractory to radioactive iodine. However, the antitumor effect and early tumor shrinkage could cause serious adverse events such as fistula formation. The optimal timing of treatment should be evaluated prior to the start of treatment with antiangiogenic TKIs. Careful attention should be paid before lenvatinib therapy started, particularly in patients with a history of surgery or radiation therapy.

Dental implant therapy is now routinely undertaken at many dental hospitals and institutions. Consequently, the incidence of complications associated with dental implant treatment has also increased.

When a dental implant becomes displaced into the maxillary sinus following dental implant placement and/or maxillary sinus augmentation surgery, the appropriate procedures for extraction of the displaced dental implant should be based on the pathophysiological conditions of the nose and paranasal sinuses.

In the case of displacement of a dental implant alone, endoscopic transnasal extraction of the dental implant using maxillary sinus fenestration (via the middle meatus and/or inferior meatus) is indicated. In subjects with nasal septum deviation and/or inferior turbinate hypertrophy, endoscopic transnasal septoplasty and/or inferior turbinotomy are also indicated for obtaining adequate working space. In patients with associated sinusitis, endoscopic transnasal sinus surgery is also indicated.

Endoscopic sinus surgery is indicated and is the procedure of first choice for the extraction of a displaced dental implant from the maxillary sinus in patients with any pathophysiological conditions of the nose and paranasal sinuses.