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.

The cases of coronavirus disease 2019 (COVID-19) mainly present with symptoms such as persistent fever, cough, and general malaise, which may become severe or fatal; while young people do not show these typical symptoms and are asymptomatic, some cases are infected with minor symptoms or none. Herein, we report a case of a 20-year-old woman who was hospitalized for infectious mononucleosis (IM). Initially, fever and sore throat were observed without typical COVID-19 symptoms, but polymerase chain reaction (PCR) tests performed before admission confirmed severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) positivity. Fortunately, she was discharged without any serious symptoms as IM and COVID-19. Virological examination suggested a primary infection with the Epstein-Barr virus. In the COVID-19 pandemic, we should also pay attention to the possibility of SARS-CoV-2 coinfection in mild and asymptomatic young cases, even if the symptoms suggesting IM are preceded.