RESUMO
BACKGROUND: Parathyroid carcinoma (PC) is a difficult-to-diagnose rare disease with low incidence. Relatively accurate preoperative diagnosis is very important in choosing surgical methods and patient prognosis. CASE SUMMARY: This study reported the clinical diagnosis and treatment of a rare patient with PC located in the thyroid gland and provided a case reference for the diagnosis and treatment of PC. A case of a 64-year-old male patient who presented to our hospital with systemic muscle and joint pain and palpitations is outlined. Subsequently, the patient was admitted to the Department of Nephrology for the treatment of "multiple myeloma nephropathy pending investigation". The patient was diagnosed with "primary hyperparathyroidism and hypercalcemic crisis" using thyroid color ultrasound. CONCLUSION: The intraoperative frozen section report considered the parathyroid tumor. Surgical tumor resection was promptly performed, and the diagnosis of PC was confirmed.