Escaping sestamibi detection: a case report of aggressive and recurrent metastatic parathyroid carcinoma.

Background: Parathyroid carcinoma is exceedingly rare. This cancer does not metastasize in a predictable manner and has in fact been noted to spread both hematogenously and lymphatically. There are currently no cases in the literature that report metastasis to a contralateral level II lymph node. Case Description: We report a case of recurrent parathyroid carcinoma in which the patient underwent several surgeries for right-sided parathyroid carcinoma and hyperparathyroidism, including 2 redo parathyroidectomies, 4 neck dissections, and auto transplantation and re-excision of the autotransplanted tissue. Almost a decade after initial surgery, parathyroid hormone (PTH) levels rose significantly, but nuclear medicine (NM) sestamibi scan, positron emission tomography-computed tomography (PET-CT), and ultrasound (US) could not identify the source of recurrent disease. Finally, neck US revealed a suspicious contralateral level II lymph node; fine needle aspiration (FNA) of the lymph node revealed parathyroid tissue, and PTH aspirate noted an elevated PTH washout. After left lateral neck dissection, pathology confirmed recurrent metastatic parathyroid carcinoma, and serum calcium and PTH levels improved. This case was further complicated by chronic kidney disease and pT1N0M0 colon cancer, all before the age of 45. Conclusions: In cases where a sestamibi scan is not able to localize a metastatic focus in a patient with known parathyroid carcinoma, FNA and PTH washout are important secondary studies. 2022 Gland Surgery. All rights reserved.