Diagnostic utility of cytology in a patient with Epstein-Barr virus-positive mucocutaneous ulcer in palatine tonsils: A case report.

Epstein-Barr virus-positive mucocutaneous ulcer (EBVMCU) is a newly established immunodeficiency-related disease. Herein, we report a case of EBVMCU and focus on its cytological usefulness for diagnosis. An 82-year-old man manifested pharyngalgia, dysphagia, and oral pain. His medical history included rheumatoid arthritis that had been treated with methotrexate. Clinically, peritonsillar abscess was suspected, but since neoplastic lesions, including malignant lymphoma (ML), could not be excluded, a series of cytohistological examination was attempted. Despite some alarming findings (e.g., frequent mitoses), fine-needle aspiration and touch imprint cytology consistently revealed a heterogeneous population of lymphoid and plasmacytoid cells with mild nuclear atypia. The final diagnosis of EBVMCU was established based on the permanent histologic specimen; however, retrospectively, cytology was more representative of the benign nature of the lesion than histology, helping a great deal to differentiate it from ML. Cytology can be a useful tool for the correct diagnosis of EBVMCU.

Functional vagal paraganglioma developing 15 years after resection of a retroperitoneal paraganglioma.

The patient, a 40-year-old woman, was diagnosed as having a functional right vagal paraganglioma (PGL) 15 years after undergoing resection for a retroperitoneal PGL. 123I-MIBG scintigraphy showed no accumulation, but as the blood noradrenaline and urinary normetanephrine concentrations were elevated, the tumor was judged as being functional, and surgery was scheduled. The patient was started on doxazosin infusion and embolization of the tumor feeding vessel was performed before the surgery. Intraoperative examination showed that the tumor was contiguous with the vagal nerve, necessitating combined resection of the vagal nerve with the tumor. Postoperatively, the catecholamine levels returned to normal range. Histopathologically, the tumor was diagnosed as a moderately differentiated, intermediate-malignant-grade PGL, with a GAPP score of 4 to 6. No non-chromaffin tissue was observed in the tumor background, so that the functional vagal PGL was considered as a sporadic metachronous tumor rather than as a metastasis from the retroperitoneal PGL. More than half of head and neck paragangliomas (HNPGLs) are reported to arise in the carotid body, and about 5% from the vagal nerve. In addition, HNPGLs rarely produce catecholamines. Herein, we consider the relationship with the previously resected retroperitoneal PGL based on a review of the literature.

Post-intubation laryngeal injury after COVID-19 treatment causing dyspnea: A report of six cases.

Severe cases of COVID-19 often require orotracheal intubation (OTI) and mechanical ventilation, and post-intubation laryngeal injury (PI-LI) is one of the important complications of OTI. Some studies have claimed that the frequency of PI-LI may be higher in COVID-19 patients as compared with that in non-COVID-19 patients, because of the larger size of endotracheal tube used, the longer OTI time, use of prone positioning of the patients, etc. Herein, we describe six cases of PI-LI who presented with dyspnea after recovering from COVID-19. Five of the patients were male and the median OTI period was 9 days. All the patients showed abnormal endoscopic findings, including posterior glottic synechiae/stenosis or subglottic/posterior glottic granulomas. Four patients required surgical intervention, including tracheostomy, laryngomicrosurgery, or laterofixation of the vocal cord. Many post-COVID-19 patients experience persistent symptoms (post-COVID-19 syndrome), including dyspnea. Two of our patients with dyspnea had been treated by internists as cases of post-COVID-19 syndrome. Therefore, we wish to underscore the need for every healthcare professional to be aware of the possibility of PI-LI after OTI, especially during the ongoing COVID-19 pandemic. Otolaryngologists should undertake endoscopic assessment of the larynx in patients presenting with dyspnea after recovering from COVID-19.

Graphene delamination from chemical vapor deposited turbostratic multilayer graphene for TEM analysis.

Turbostratic multilayer graphene (MLG) is of great interest due to its unique electronic properties resulting from a linear band dispersion at the K point, which is similar to that of single-layer graphene. The band structure is derived from the stacking structure of turbostratic MLG where graphene layers have random in-plane rotations with respect to each other. Although wafer-scale growth of turbostratic MLG has been demonstrated, the crystallinity of individual graphene layers is still challenging to investigate. In this study, we present a new approach to reveal the grain structure of turbostratic MLG by transmission electron microscopy (TEM) observation. Mechanical delamination is demonstrated for the chemical vapor deposited MLG to peel off the topmost graphene layers by using a polydimethylsiloxane sheet. Micrometer-scale patterning of the MLG prior to the delamination is found to be effective to obtain graphene films with the designed shape and arrangement. Furthermore, the delaminated graphene films are successfully transferred onto a TEM grid, enabling us to estimate the grain size of the turbostratic MLG. This method is potentially applicable for not only preparing samples but also fabricating vertically stacked heterostructure devices using 2D materials.