Reverse-transcription polymerase chain reaction (RT-PCR) testing is necessary for the definitive diagnosis of coronavirus disease 2019 (COVID-19) , and is most often performed on pharyngeal swabs. However, it has become clear that even if the RT-PCR is negative, COVID-19 cannot be ruled out altogether. We encountered a patient who developed COVID-19 after a tracheostomy. He developed fever and respiratory failure and was suspected as having developed COVID-19, but RT-PCR conducted on upper airway specimens was negative twice in succession ; a third RT-PCR test conducted on a sputum specimen later confirmed a positive result for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) . In cases with clinically suspected infection with SARS-CoV-2, RT-PCR should be repeated, and lower respiratory tract specimens should be used from the beginning if the infection occurs before or after tracheostomy.

　Sinonasal inverted papilloma is the most commonly occurring benign tumor of the paranasal sinuses and is generally recognized as being unilateral. It has the potential for malignant transformation and is known to be associated with a high relapse rate. Herein, we report two cases of bilateral sinonasal inverted papilloma which were diagnosed at surgery. Preoperative biopsy suggested that the nasal tumor was an inflammatory nasal polyp, but frozen section examination revealed the diagnosis of bilateral inverted papilloma. Even in cases where a diagnosis of unilateral sinonasal inverted papilloma has been made, it must be assumed that there could be a neoplastic lesion on the opposite side. Therefore, detailed intranasal observation is important. In some cases, preoperative histological diagnosis and intra-operative diagnosis are essential.

　Hypochlorite is often used as a household detergent in Japan, and is included as an ingredient of commercial cleaning products manufactured by multiple companies. Precautions for use, such as prohibition against combined use with acidic cleaning solutions, ensuring proper ventilation, and recommendation for wearing masks, gloves, goggles, etc., have been published. However, even with the use of proper precautions, including ensuring adequate, health problems could still occur, and among them, reported on social networking services (SNS) , is olfactory dysfunction. There are no published papers yet on the association of olfactory dysfunction with the use of hypochlorite. We encountered two cases of olfactory dysfunction that developed after the subjects used chlorine-based cleaning agents. Hypochlorous acid and organochlorine compounds, which are metabolites, may cause olfactory inflammation and conductive olfactory dysfunction, and repeated exposure to hypochlorous acid impairs regeneration of the olfactory epithelium and homeostasis, and inflammatory cell infiltration. It can cause neurological damage, resulting in neurological olfactory dysfunction. When using chlorine-based cleaning agents, it is important to observe the precautions for use, and in the event of occurrence of olfactory dysfunction, use of the agent should be immediately discontinued and a specialized medical institution consulted.

　We describe the case of a patient who underwent middle ear surgery and subsequently developed a bone defect in the middle cranial fossa, resulting in the occurrence of a meningoencephalocele and cerebrospinal fluid otorrhea due to a traumatic defect of the arachnoid membrane. The patient was a 19-year-old man who had previously undergone two middle ear surgeries for chronic otitis media at the ages of 9 and 10 years old. He developed unilateral hearing loss in the right ear, as well as headache and watery otorrhea after these surgeries. A pulsating tumor lesion was identified in the ear canal, and temporal bone computed tomography revealed the presence of a bone defect in the right middle cranium, as well as dense soft tissue in the right canal and mastoid cavity. Furthermore, magnetic resonance imaging revealed herniation of the brain parenchyma. Based on these findings, the patient was diagnosed as having a meningoencephalocele in the right temporal bone and underwent surgery. An extensive bone defect was identified in the base of the middle cranial fossa. Furthermore, loss of the dura mater and herniation of the brain tissue into the mastoid cavity were observed. Following resection of the meningoencephalocele, the bone defect was closed in a multi-layered fashion using a pedicled temporalis muscle flap, temporal fascia, rectus fascia, adipose tissue, and an absorbable plate for internal fixation. At 2 years 5 months after the surgery, the patient has not developed meningitis or recurrence of the cerebrospinal fluid otorrhea. Iatrogenic meningoencephalocele is a relatively rare condition, and an appropriate treatment approach should be selected taking into account multiple factors, such as the size and location of the fistula and the level of residual hearing.

　Primary infection with varicella-zoster virus (VZV) causes fever, erythema and pustules on the whole body, and the virus remains in latent form in the ganglia. Ramsay Hunt syndrome is caused by reactivation of latent VZV, mainly in the geniculate ganglia, via the facial nerve sensory branches, and has three main features : facial nerve palsy, auricular shingles, and vestibular and cochlear nerve symptoms. In this study, we report our experience of five cases that also had other multiple cranial neuropathies. Some of the cases did not have facial nerve palsy and some cases developed facial nerve palsy than other cranial neuropathies. The clinical course varied among the cases. Some patients had meningitis or cerebral infarction. VZV infection is recognized to be associated with a diversity of neuropathy sites and order of appearance of symptoms. We also provide an overview of the pathogenesis, diagnosis, treatment and prognosis, along with a brief review of the literature. Although the geniculate ganglion is a common site for latent VZV, the vagal, cochlear, and vestibular ganglia are also reported as sites of latent VZV. Blood tests and cerebrospinal fluid tests are useful for the diagnosis of VZV infection, but cerebrospinal fluid testing was the most often used in our cases. For treatment, ACV or PSL is commonly used, and there are no clear recommendations. VZV infection resulting in multiple cerebral neuropathies carries a rather poor prognosis and patients need to be followed up for at least a year.

　Syphilis is a systemic chronic inflammatory disease caused by the bacterium Treponema pallidum. Patients with syphilis often visit urology and dermatology clinics with skin and pudendal lesions. We encountered a case of pharyngeal syphilis with only characteristic oropharyngeal lesions. The patient was a 30-year-old man with a 2-month history of sore throat and tongue pain. At his first consultation, milky white spots were observed on the palatine tonsils bilaterally and on the uvula, presenting a “butterfly appearance” characteristic of pharyngeal syphilis, and on the left margin of the tongue, along with erosive lesions on the mucosa of the lower lip. Biopsy of a milky white spot on the left margin of the tongue revealed band-shaped inflammatory cell infiltration under the mucosa in hematoxylin-eosin stained sections, and positive region in the epidermis in specific antibody immunostaining against syphilis revealed, so that the patient was diagnosed as having pharyngeal syphilis. Both the Treponema pallidum haemagglutination and rapid plasma reagin (RPR) tests were positive. Since a biopsy was performed, the patient was treated with amoxicillin 1500 mg/day for 3 days. One week later, the mucosal lesions in the oropharynx were no longer visible to the naked eye. The amoxicillin dose was then reduced to 750 mg/day and the lesions did not recur. The test value in the RPR test decreased to meet the criterion for cure criteria, and the treatment was completed at 27 weeks. Syphilis typically presents with skin and genital lesions, but some patients lack typical skin and genital lesions and might only have oropharyngeal lesions. This case report serves to underscore the need for physicians to bear in mind the possibility of syphilis when they see characteristic oropharyngeal lesions, even in the absence of typical skin and urogenital lesions.