In regard to post-injury tissue regeneration of the larynx and trachea, knowledge regarding the cellular composition of normal tissue and maintenance of its homeostasis, which are fundamental for achieving normalization, remains limited. Cell lineage tracing experiments and organoid fabrication methods have enabled the demonstration of stem cell identities by producing all cell types constituting a tissue from a single cell, while retaining self-renewal capacity. By these two methods, several tissue stem cells of the trachea have been identified, while tissue stem cells of the larynx have not been identified yet.

New technologies have emerged, such as single-cell RNA sequencing for analyzing the genetic information of individual cells and RNAscope for highly sensitive in situ hybridization to visualize cellular localization. These techniques can be employed to explore and validate candidate tissue stem cells. This paper introduces these promising technologies for identifying novel stem cell candidates and outlines the current state of tissue stem cell research related to the larynx and trachea.

The clinical/demographic backgrounds of patients with sudden sensorineural hearing loss (SSNHL) vary from healthy young people to elderly people with multiple pre-existing diseases. Herein, we report the case of a 65-year-old male lung adenocarcinoma patient with brain metastasis who presented with SSNHL in the left ear. As expected from the pre-existing disease, brain MRI suggested metastatic disease in the left internal auditory canal including the cochlear nerve fibers, as the cause of the SSNHL. With steroid administration, the pure tone audiometry thresholds on the left side improved within one week, even though the speech discrimination score of the left ear was low. After two months, further improvement of the pure tone audiometry thresholds in the left ear was observed, but the hearing level at high frequencies in the right ear was notably worse as compared with that at the patient’s first visit.

SSNHL carrying a poor prognosis has occasionally been reported to be caused by metastasis in the internal auditory canal in patients with any adenocarcinoma. Interestingly, the hearing thresholds in our SSNHL patient improved markedly with steroid administration, which is rather rare, even though his speech discrimination score was low. The differences in the onset times and severity of sensorineural hearing loss between the left and right ears could possibly be explained by differences in the time of onset and size of the metastatic tumors in the auditory pathway between the two sides, although we could not find any evidence of metastatic disease in the right internal auditory canal in this patient, even on follow-up MRI.

In conclusion, we encountered a case of metastatic lung adenocarcinoma who presented with bilateral SSNHL. MRI was useful for the diagnosis of SSNHL caused by metastasis in the internal auditory canal from the lung adenocarcinoma. The cause of SSNHL is often difficult to determine, but the patient’s background is sometimes helpful for a definitive diagnosis of the cause of SSNHL.

Malignant melanoma, a highly aggressive cancer, originates from melanocytic cells. The skin is the most common primary site, with cases of the cancer arising from the mucosa accounting for about 9.5% of all cases. Mucosal melanoma most frequently arises in the sinonasal cavity, and primary onset in the eustachian tube is extremely rare. While the prognosis of mucosal melanoma is generally poor, we encountered a case of long-term survival following treatment with a combination of surgery and radiation therapy. A 50-year-old woman was admitted to our hospital with the complaints of left-sided otalgia and recurrent otitis media. Initial physical examination revealed a dark brownish tumor in the left pharyngeal orifice of the eustachian tube. Based on this finding and findings in the subsequent contrast-enhanced MRI and biopsy examinations, we diagnosed the patient as having stage III (cT3N0M0: UICC 8th edition) mucosal melanoma. We performed en-bloc resection of the eustachian tube via a transpalatal approach, followed by postoperative radiotherapy (60 Gy in 30 fractions). At present, 6 years after completion of the above treatment, the patient remains well, without any signs of recurrence. Herein, we report on the outcome of treatment of a patient with mucosal melanoma of the eustachian tube, along with a review of literature. Appropriate choice of treatment and an adequate incision margin at surgery might help in overcoming the unfavorable prognosis of mucosal melanoma.

While tuberculosis (TB) is on the decline in Japan, the incidence is higher than that in other industrialized countries. Among cases of extrapulmonary TB, tuberculous otitis media is rare, and the diagnosis is often delayed because of the variety of symptoms. We report a case of tuberculous otitis media in a patient who was diagnosed as having pulmonary TB during treatment for refractory otitis media and the middle ear lesions improved with antituberculosis drug therapy. The patient, a 26-year-old woman with the complaints of hearing loss and otorrhea visited our hospital after the hearing loss failed to improve with treatment provided by a local doctor. On examination, her external auditory canal was swollen, the tympanic membrane could not be visualized, and an audiogram showed bilateral conductive hearing loss. Auricular CT showed bilateral mastoid apicitis and soft shadows in the tympanic chamber, without bony destruction. Suspecting eosinophilic otitis media or ANCA-associated vasculitis otitis media, we started the patient on steroid treatment and performed ear washing, but the patient’s symptoms deteriorated. A QFT was performed on the suspicion of tuberculous otitis media, and a chest CT revealed findings suggestive of pulmonary TB, which was confirmed by transbronchial lung biopsy. After the patient was started on antituberculosis drug therapy, her symptoms improved. Since the patient’s refractory otitis media improved with treatment administered for pulmonary TB, we made a clinical diagnosis of tuberculous otitis media. In patients presenting with refractory otitis media, tuberculous otitis media should be considered in the differential diagnosis and aggressive examination should be performed to rule out the disease.

Tuberculosis infections encountered in otorhinolaryngological practice include tuberculous lymphadenitis, pharyngeal tuberculosis, and tuberculous otitis media. The majority of cases are cases of secondary tuberculosis, and primary cases are rarely reported. In particular, primary nasopharyngeal tuberculosis is an extremely rare disease, with only a few reported cases from Japan. We report the case of a 51-year-old female patient with a lesion in the right nasopharynx. The patient had suffered from a sore throat of unknown cause for a year and was referred to our hospital for further investigation. Fiberoptic nasal endoscopic examination revealed an elevated lesion with a white membrane in the right nasopharynx. Biopsy revealed nasopharyngeal tuberculosis. Imaging studies showed no lung lesions, and we made a diagnosis of primary nasopharyngeal tuberculosis. After multidrug antituberculosis therapy as used for pulmonary tuberculosis, the raised lesion with the white membrane disappeared. In addition, sputum culture was negative, and the patient was considered cured. Nasopharyngeal tuberculosis manifests with nonspecific symptoms such as cervical lymphadenopathy, otorrhea, and sore throat. There are also no characteristic local findings. Early diagnosis is important because delay in diagnosis can lead to spread of secondary infection. Therefore, nasopharyngeal tuberculosis should be included in the differential diagnosis of nasopharyngeal lesions.

Introduction: Obstruction from any cause can cause dilatation of the parotid duct, which is commonly referred to as parotid duct dilatation. In some cases, the cause of the stenosis is obvious, such as inflammation, salivary stones, tumors, or trauma, while in others, the so-called cases of idiopathic parotid duct dilatation, the cause remains unknown. Herein, we report a case of a salivary gland duct cyst with cystic dilatation of the left parotid duct.

Case: A 53-year-old woman first noticed swelling of the left cheek while eating more than 10 years before her first visit to our department. When she applied pressure on the left cheek, saliva flowed into the oral cavity and the swelling subsided. Similar episodes had occurred repeatedly, about once a week. About 5 months before her first visit to our department, her left buccal swelling failed to improve even with compression of the cheek, and she visited a doctor 3 months before her first visit to our department. Ultrasonography showed dilatation of the left parotid duct, which led to the suspicion of parotid duct obstruction, and she was referred to our department for further examination and treatment. Imaging examinations and biochemical tests of the cystic fluid obtained by aspiration revealed cystic dilatation of the parotid duct. In addition, as a bougie could not be passed through the parotid duct, obstruction was suspected, and we made the diagnosis of parotid duct dilatation. The patient was operated upon under general anesthesia with the goal of radical treatment. As the approach to the parotid duct orifice was as difficult as before the operation, the cyst was opened incised through the mouth and an orifice was formed by suturing the oral mucosa to the cyst wall. Postoperative pathology results confirmed the diagnosis of a parotid duct cyst. The swelling episodes of the cheek resolved postoperatively, and have not recurred to date, three months after the operation.

Conclusion: Ultrasonography, MRI, fine needle aspiration cytology (FNAC) and fluid aspirate examination were useful for preoperative diagnosis of the left parotid duct cyst, and a transoral window opening was useful for radical treatment.

Schwannomas of the hypopharynx are rare, and no standard treatment has been established. In this report, we describe a case of a submucosal tumor of the hypopharynx that was diagnosed as a schwannoma based on the findings of magnetic resonance imaging (MRI). We undertook treatment by transoral resection using the continuous aspiration syringe method. We report this case with a review of the literature. A 63-year-old woman visited a neighborhood clinic complaining of throat discomfort. She was referred to our hospital for closer examination and treatment of a submucosal tumor in the left piriform recess and motor disturbance of the left vocal cord. MRI showed a tumor measuring 27 mm in greatest diameter in the left hypopharynx, that was visualized as a low signal intensity on T1-weighted images and as a high signal intensity on T2-weighted images. We diagnosed the patient as having a schwannoma and performed transoral resection. We were able to easily dissect the tumor and remove it en bloc using the continuous aspiration syringe method during deep manipulation. The tumor was confirmed as a schwannoma based on postoperative pathological examination. The patient’s throat discomfort and vocal fold movement disorder improved after the surgery. In Japan, the most commonly reported site of origin of pharyngeal schwannomas is the hypopharynx, and in many cases, transoral resection is performed. In the present case, the tumor was 27 mm in greatest diameter, and we were able to remove it en bloc using the continuous aspiration syringe method. Thus, the continuous aspiration syringe method is considered as useful for transoral resection of schwannomas.

Tonsillectomy is one of the most frequently performed surgical procedures in the field of otorhinolaryngology and is one of the first procedures that otorhinolaryngologists learn. Of the surgical complications, postoperative hemorrhage requires special attention because of the associated risk of airway obstruction. We investigated the risk factors for postoperative bleeding in patients who underwent tonsillectomy at our hospital. A total of 164 patients who underwent palatoglossus tonsillectomy at our hospital during the 5-year period between January 2018 and December 2022 were included in the study. Postoperative bleeding was defined as bleeding from the surgical wound or the presence of a clot in the surgical wound at the time of examination. The patient’s sex and age, indications for surgery, presence/absence of underlying hypertension and diabetes mellitus, body mass index (BMI), use of antithrombotic drugs, smoking status, and years of experience of the surgeon were extracted from medical records, and the patients were divided into two groups: the postoperative bleeding group and the non-postoperative bleeding group. After variable selection using the χ-square test and stepwise elimination method, multivariate logistic regression analysis was performed. The χ-square test showed a significant difference for habitual tonsillitis, and multivariate analysis showed that only habitual tonsillitis was selected (odds ratio = 7.27, P < 0.001). Although not statistically significant, there was a trend toward a higher risk of postoperative bleeding in males (odds ratio = 2.30, P = 0.062). Habitual tonsillitis was identified as a risk factor for postoperative hemorrhage, with a trend toward a higher risk of postoperative hemorrhage in men. Habitual tonsillitis is thought to increase the risk of postoperative bleeding because repeated inflammation causes adhesions to the surrounding tissues and neovascular vessel formation.

A deep neck abscess is a bacterial infection that most often develops as a complication of upper respiratory infections or dental diseases, but in rare cases, they are secondary to head and neck cancers. Herein, we report a case of pharyngoesophageal diverticulum carcinoma complicated by a deep neck abscess. A 78-year-old man presented with pharyngeal discomfort and difficulty in swallowing. He originally had a pharyngoesophageal diverticulum. CT indicated a deep neck abscess. We performed emergent tracheotomy and surgical drainage. At the time, we thought that the deep neck abscess was secondary to infection of the esophageal diverticulum. Four months after the operation, however, the patient presented with hoarseness of voice, and fiberoptic laryngoscopy revealed right vocal cord paralysis. CT revealed a tumorous lesion on the right side of the esophagus invading the surrounding right lobe of the thyroid gland and trachea. Fine needle aspiration cytology of the tumor suggested squamous cell carcinoma. We performed total laryngopharyngectomy with cervical esophagectomy and bilateral neck dissection. Postoperatively, the patient was diagnosed as having a pharyngoesophageal diverticulum carcinoma (pT4bN2M0).

Esophageal diverticulum carcinoma is rare, accounting for 0.03%–0.2% of all esophageal cancers. Pharyngoesophageal diverticulum carcinoma is even rarer, with only a very few cases reported. However, to the best of our knowledge, this is the first reported case of pharyngoesophageal diverticulum carcinoma complicated by a deep neck abscess. Diagnosis of malignancy was delayed in this case, and a biopsy of the abscess wall at the time of the surgical drainage or an early fine needle aspiration cytology could have led to an earlier diagnosis. In patients presenting with a deep neck abscess, the possibility of head and neck cancer as the cause should be considered.