Effective long-term management of parathyromatosis-related refractory hypercalcemia with a combination of denosumab and cinacalcet treatment.

Parathyromatosis is a rare cause of persistent or recurrent primary hyperparathyroidism and hypercalcemia due to the presence of hyperfunctioning foci of parathyroid tissue in the neck and/or mediastinum. We describe the case of a male patient who presented with severe hypercalcemia and a left-sided palpable parathyroid mass. Over the course of the next 18 years, the patient underwent neck exploration surgery on multiple occasions due to recurrent primary hyperparathyroidism and refractory hypercalcemia, complicated by nephrolithiasis and impairment of renal function, while bone mineral density was preserved. Histological findings and the natural course of the disease were consistent with parathyromatosis. Medical interventions with oral bisphosphonates or high-dose cinacalcet failed to control the patient's hypercalcemia. The combination of monthly denosumab and cinacalcet was, however, successful in maintaining the patient's serum calcium in the normal/upper-normal range over a 36-month period with no significant side effects. This is the first report of off-label denosumab use in combination with cinacalcet in the long-term management of parathyromatosis-related refractory hypercalcemia.

Thyroiditis following vaccination against COVID-19: Report of two cases and review of the literature.

INTRODUCTION: Immune response following viral infections has been suggested as a probable mechanism leading to subacute thyroiditis (SAT). A few cases of SAT following SARS-CoV-2 infection have been described since the outbreak of the pandemic in 2019. Cases of SAT after vaccination against influenza have also been reported. We describe two female patients with thyroiditis after vaccination against SARS-CoV-2. PRESENTATION OF CASES: The first patient presented with fever and pain in the thyroid area typical of SAT two weeks after vaccination with the BNT162B2 mRNA (Pfizer-BioNTech) COVID-19 vaccine. The second patient presented with biochemical and imaging features consistent with silent thyroiditis three weeks after vaccination with the ChAdOx1-S (AstraZeneca) vaccine. Both patients were asymptomatic prior to vaccination and PCR of nasopharyngeal swab for SARS-CoV-2 and other respiratory viruses associated with SAT was negative. Serology testing for measles, mumps, rubella, CMV and EBV viruses was suggestive of immunity. Antibody titre against spike S protein of SARS-CoV-2 was measured for both patients and was indicative of adequate post vaccination antibody response. Two months after initial assessment, both patients were euthyroid and asymptomatic. CONCLUSIONS: Subacute as well as silent thyroiditis may rarely occur after vaccination against COVID-19. Further research is needed to investigate the prevalence and pathogenesis of thyroid dysfunction following vaccination against COVID-19.